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  • 1. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Ampe, J.
    Anderson, B.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Bagagli, R.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bartelt, J.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bédérède, D.
    Bellardi, F.
    Bellazzini, R.
    Belli, F.
    Berenji, B.
    Bisello, D.
    Bissaldi, E.
    Bloom, E. D.
    Bogaert, G.
    Bogart, J. R.
    Bonamente, E.
    Borgland, A. W.
    Bourgeois, P.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Busetto, G.
    Caliandro, G. A.
    Cameron, R. A.
    Campell, M.
    Caraveo, P. A.
    Carius, S.
    Carlson, P.
    Casandjian, J. M.
    Cavazzuti, E.
    Ceccanti, M.
    Cecchi, C.
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Chipaux, R.
    Cillis, A. N.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Condamoor, S.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Corbet, R.
    Cutini, S.
    Davis, D. S.
    Deklotz, M.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    Dizon, P.
    Dormody, M.
    Do Couto E Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Edmonds, Y.
    Fabiani, D.
    Farnier, C.
    Favuzzi, C.
    Ferrara, E. C.
    Ferreira, O.
    Fewtrell, Z.
    Flath, D. L.
    Fleury, P.
    Focke, W. B.
    Fouts, K.
    Frailis, M.
    Freytag, D.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Goodman, J.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hakimi, M.
    Haller, G.
    Hanabata, Y.
    Hart, P. A.
    Hascall, P.
    Hays, E.
    Huffer, M.
    Hughes, R. E.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kavelaars, A.
    Kelly, H.
    Kerr, M.
    Klamra, W.
    Knödlseder, J.
    Kocian, M. L.
    Kuehn, F.
    Kuss, M.
    Latronico, L.
    Lavalley, C.
    Leas, B.
    Lee, B.
    Lee, S.-H.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Lung, D. K.
    Madejski, G. M.
    Makeev, A.
    Marangelli, B.
    Marchetti, M.
    Massai, M. M.
    May, D.
    Mazzenga, G.
    Mazziotta, M. N.
    McEnery, J. E.
    McGlynn, S.
    Meurer, C.
    Michelson, P. F.
    Minuti, M.
    Mirizzi, N.
    Mitra, P.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Mongelli, M.
    Monte, C.
    Monzani, M. E.
    Moretti, E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nelson, D.
    Nilsson, L.
    Nishino, S.
    Nolan, P. L.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paccagnella, A.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Picozza, P.
    Pinchera, M.
    Piron, F.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Rapposelli, E.
    Raynor, W.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Reyes, L. C.
    Ritz, S.
    Robinson, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, F.
    Sacchetti, A.
    Sadrozinski, H. F.-W.
    Saggini, N.
    Sanchez, D.
    Sander, A.
    Sapozhnikov, L.
    Saxton, O. H.
    Saz Parkinson, P. M.
    Sellerholm, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Sgrò, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J.-L.
    Stephens, T. E.
    Strickman, M. S.
    Strong, A. W.
    Sugizaki, M.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Tenze, A.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Tibolla, O.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Turri, M.
    Usher, T. L.
    Vilchez, N.
    Virmani, N.
    Vitale, V.
    Wai, L. L.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, D. L.
    Wood, K. S.
    Yasuda, H.
    Ylinen, T.
    Ziegler, M.
    The on-orbit calibration of the Fermi Large Area Telescope2009Ingår i: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 32, nr 3-4, s. 193-219Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.

  • 2. Abdo, A A
    et al.
    Ackermann, M
    Ajello, M
    Anderson, B
    Atwood, W B
    Axelsson, M
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L
    Ballet, J
    Barbiellini, G
    Baring, M G
    Bastieri, D
    Baughman, B M
    Bechtol, K
    Bellazzini, R
    Berenji, B
    Bignami, G F
    Blandford, R D
    Bloom, E D
    Bonamente, E
    Borgland, A W
    Bregeon, J
    Brez, A
    Brigida, M
    Bruel, P
    Burnett, T H
    Caliandro, G A
    Cameron, R A
    Caraveo, P A
    Casandjian, J M
    Cecchi, C
    Celik, O
    Chekhtman, A
    Cheung, C C
    Chiang, J
    Ciprini, S
    Claus, R
    Cohen-Tanugi, J
    Conrad, J
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cutini, S
    Dermer, C D
    de Angelis, A
    de Luca, A
    de Palma, F
    Digel, S W
    Dormody, M
    do Couto e Silva, E
    Drell, P S
    Dubois, R
    Dumora, D
    Farnier, C
    Favuzzi, C
    Fegan, S J
    Fukazawa, Y
    Funk, S
    Fusco, P
    Gargano, F
    Gasparrini, D
    Gehrels, N
    Germani, S
    Giebels, B
    Giglietto, N
    Giommi, P
    Giordano, F
    Glanzman, T
    Godfrey, G
    Grenier, I A
    Grondin, M-H
    Grove, J E
    Guillemot, L
    Guiriec, S
    Gwon, C
    Hanabata, Y
    Harding, A K
    Hayashida, M
    Hays, E
    Hughes, R E
    Jóhannesson, G
    Johnson, R P
    Johnson, T J
    Johnson, W N
    Kamae, T
    Katagiri, H
    Kataoka, J
    Kawai, N
    Kerr, M
    Knödlseder, J
    Kocian, M L
    Kuss, M
    Lande, J
    Latronico, L
    Lemoine-Goumard, M
    Longo, F
    Loparco, F
    Lott, B
    Lovellette, M N
    Lubrano, P
    Madejski, G M
    Makeev, A
    Marelli, M
    Mazziotta, M N
    McConville, W
    McEnery, J E
    Meurer, C
    Michelson, P F
    Mitthumsiri, W
    Mizuno, T
    Monte, C
    Monzani, M E
    Morselli, A
    Moskalenko, I V
    Murgia, S
    Nolan, P L
    Norris, J P
    Nuss, E
    Ohsugi, T
    Omodei, N
    Orlando, E
    Ormes, J F
    Paneque, D
    Parent, D
    Pelassa, V
    Pepe, M
    Pesce-Rollins, M
    Pierbattista, M
    Piron, F
    Porter, T A
    Primack, J R
    Rainò, S
    Rando, R
    Ray, P S
    Razzano, M
    Rea, N
    Reimer, A
    Reimer, O
    Reposeur, T
    Ritz, S
    Rochester, L S
    Rodriguez, A Y
    Romani, R W
    Ryde, F
    Sadrozinski, H F-W
    Sanchez, D
    Sander, A
    Saz Parkinson, P M
    Scargle, J D
    Sgrò, C
    Siskind, E J
    Smith, D A
    Smith, P D
    Spandre, G
    Spinelli, P
    Starck, J-L
    Strickman, M S
    Suson, D J
    Tajima, H
    Takahashi, H
    Takahashi, T
    Tanaka, T
    Thayer, J G
    Thompson, D J
    Tibaldo, L
    Tibolla, O
    Torres, D F
    Tosti, G
    Tramacere, A
    Uchiyama, Y
    Usher, T L
    Van Etten, A
    Vasileiou, V
    Vilchez, N
    Vitale, V
    Waite, A P
    Wang, P
    Watters, K
    Winer, B L
    Wolff, M T
    Wood, K S
    Ylinen, T
    Ziegler, M
    Detection of 16 gamma-ray pulsars through blind frequency searches using the Fermi LAT.2009Ingår i: Science (New York, N.Y.), ISSN 1095-9203, Vol. 325, nr 5942, s. 840-4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pulsars are rapidly rotating, highly magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there are more than 1800 known radio pulsars, until recently only seven were observed to pulse in gamma rays, and these were all discovered at other wavelengths. The Fermi Large Area Telescope (LAT) makes it possible to pinpoint neutron stars through their gamma-ray pulsations. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants. Direct detection of gamma-ray pulsars enables studies of emission mechanisms, population statistics, and the energetics of pulsar wind nebulae and supernova remnants.

  • 3. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Anderson, B.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cecchi, C.
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Dereli, H.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    di Bernardo, G.
    Dormody, M.
    Do Couto E Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Edmonds, Y.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gaggero, D.
    Gargano, F.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Hughes, R. E.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knödlseder, J.
    Kocian, M. L.
    Kuehn, F.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Nuss, E.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rodriguez, A. Y.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Sellerholm, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Sgrò, C.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J.-L.
    Stecker, F. W.
    Striani, E.
    Strickman, M. S.
    Strong, A. W.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes2009Ingår i: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 103, nr 25, s. 1101-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The diffuse galactic γ-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess γ-ray emission ≳1GeV relative to diffuse galactic γ-ray emission models consistent with directly measured CR spectra (the so-called “EGRET GeV excess”). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse γ-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10°≤|b|≤20°. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic γ-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.

  • 4. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Asano, K.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bhat, P. N.
    Bissaldi, E.
    Bloom, E. D.
    Bonamente, E.
    Bonnell, J.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Briggs, M. S.
    Brigida, M.
    Bruel, P.
    Burgess, J. M.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cecchi, C.
    Çelik, Ö.
    Chaplin, V.
    Charles, E.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Connaughton, V.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cutini, S.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    Dingus, B. L.
    Do Couto E Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Finke, J.
    Fishman, G.
    Focke, W. B.
    Foschini, L.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Gibby, L.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Granot, J.
    Greiner, J.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Grupe, D.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Hoversten, E. A.
    Hughes, R. E.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Kippen, R. M.
    Knödlseder, J.
    Kocevski, D.
    Kouveliotou, C.
    Kuehn, F.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McBreen, S.
    McEnery, J. E.
    McGlynn, S.
    Mészáros, P.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Moretti, E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paciesas, W. S.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Petrosian, V.
    Piron, F.
    Porter, T. A.
    Preece, R.
    Rainò, S.
    Ramirez-Ruiz, E.
    Rando, R.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Schalk, T. L.
    Sgrò, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Stamatikos, M.
    Stecker, F. W.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Toma, K.
    Torres, D. F.
    Tosti, G.
    Troja, E.
    Uchiyama, Y.
    Uehara, T.
    Usher, T. L.
    van der Horst, A. J.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    von Kienlin, A.
    Waite, A. P.
    Wang, P.
    Wilson-Hodge, C.
    Winer, B. L.
    Wood, K. S.
    Wu, X. F.
    Yamazaki, R.
    Ylinen, T.
    Ziegler, M.
    the Fermi LAT Collaboration,
    A limit on the variation of the speed of light arising from quantum gravity effects2009Ingår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 462, nr 7271, s. 331-334Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A cornerstone of Einstein’s special relativity is Lorentz invariance—the postulate that all observers measure exactly the same speed of light in vacuum, independent of photon-energy. While special relativity assumes that there is no fundamental length-scale associated with such invariance, there is a fundamental scale (the Planck scale, lPlanck~1.62×10-33cm or EPlanck = MPlanckc2~1.22×1019GeV), at which quantum effects are expected to strongly affect the nature of space–time. There is great interest in the (not yet validated) idea that Lorentz invariance might break near the Planck scale. A key test of such violation of Lorentz invariance is a possible variation of photon speed with energy. Even a tiny variation in photon speed, when accumulated over cosmological light-travel times, may be revealed by observing sharp features in γ-ray burst (GRB) light-curves. Here we report the detection of emission up to ~31GeV from the distant and short GRB090510. We find no evidence for the violation of Lorentz invariance, and place a lower limit of 1.2EPlanck on the scale of a linear energy dependence (or an inverse wavelength dependence), subject to reasonable assumptions about the emission (equivalently we have an upper limit of lPlanck/1.2 on the length scale of the effect). Our results disfavour quantum-gravity theories in which the quantum nature of space–time on a very small scale linearly alters the speed of light.

  • 5. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Asano, K.
    Atwood, W. B.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bhat, P. N.
    Bissaldi, E.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Briggs, M. S.
    Brigida, M.
    Bruel, P.
    Burgess, J. M.
    Burrows, D. N.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cecchi, C.
    Çelik, Ö.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Connaughton, V.
    Conrad, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cutini, S.
    d'Elia, V.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    Dingus, B. L.
    Silva, E. do Couto e.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Finke, J.
    Fishman, G.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gehrels, N.
    Germani, S.
    Giavitto, G.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Goldstein, A.
    Granot, J.
    Greiner, J.
    Grenier, I. A.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Horan, D.
    Hughes, R. E.
    Jackson, M. S.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Kippen, R. M.
    Knödlseder, J.
    Kocevski, D.
    Komin, N.
    Kouveliotou, C.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McBreen, S.
    McEnery, J. E.
    McGlynn, S.
    Meegan, C.
    Mészáros, P.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Moretti, E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Paciesas, W. S.
    Paneque, D.
    Panetta, J. H.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Petrosian, V.
    Piron, F.
    Porter, T. A.
    Preece, R.
    Rainò, S.
    Rando, R.
    Rau, A.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Roming, P. W. A.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Schalk, T. L.
    Sgrò, C.
    Siskind, E. J.
    Smith, P. D.
    Spinelli, P.
    Stamatikos, M.
    Stecker, F. W.
    Stratta, G.
    Strickman, M. S.
    Suson, D. J.
    Swenson, C. A.
    Tajima, H.
    Takahashi, H.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Uehara, T.
    Usher, T. L.
    van der Horst, A. J.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    von Kienlin, A.
    Waite, A. P.
    Wang, P.
    Wilson-Hodge, C.
    Winer, B. L.
    Wood, K. S.
    Yamazaki, R.
    Ylinen, T.
    Ziegler, M.
    Fermi Observations of GRB 090902B: A Distinct Spectral Component in the Prompt and Delayed Emission2009Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 706, nr 1, s. L138-L144Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on the observation of the bright, long gamma-ray burst (GRB), GRB 090902B, by the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) instruments on-board the Fermi observatory. This was one of the brightest GRBs to have been observed by the LAT, which detected several hundred photons during the prompt phase. With a redshift of z = 1.822, this burst is among the most luminous detected by Fermi. Time-resolved spectral analysis reveals a significant power-law component in the LAT data that is distinct from the usual Band model emission that is seen in the sub-MeV energy range. This power-law component appears to extrapolate from the GeV range to the lowest energies and is more intense than the Band component, both below ~50 keV and above 100 MeV. The Band component undergoes substantial spectral evolution over the entire course of the burst, while the photon index of the power-law component remains constant for most of the prompt phase, then hardens significantly toward the end. After the prompt phase, power-law emission persists in the LAT data as late as 1 ks post-trigger, with its flux declining as t –1.5. The LAT detected a photon with the highest energy so far measured from a GRB, 33.4+2.7 –3.5 GeV. This event arrived 82 s after the GBM trigger and ~50 s after the prompt phase emission had ended in the GBM band. We discuss the implications of these results for models of GRB emission and for constraints on models of the extragalactic background light

  • 6. Abdo, A A
    et al.
    Ackermann, M
    Ajello, M
    Atwood, W B
    Axelsson, M
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L
    Ballet, J
    Barbiellini, G
    Baring, M G
    Bastieri, D
    Baughman, B M
    Bechtol, K
    Bellazzini, R
    Berenji, B
    Bignami, G F
    Blandford, R D
    Bloom, E D
    Bonamente, E
    Borgland, A W
    Bregeon, J
    Brez, A
    Brigida, M
    Bruel, P
    Burnett, T H
    Caliandro, G A
    Cameron, R A
    Camilo, F
    Caraveo, P A
    Carlson, P
    Casandjian, J M
    Cecchi, C
    Celik, O
    Charles, E
    Chekhtman, A
    Cheung, C C
    Chiang, J
    Ciprini, S
    Claus, R
    Cognard, I
    Cohen-Tanugi, J
    Cominsky, L R
    Conrad, J
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Corbet, R
    Cutini, S
    Dermer, C D
    Desvignes, G
    de Angelis, A
    de Luca, A
    de Palma, F
    Digel, S W
    Dormody, M
    do Couto e Silva, E
    Drell, P S
    Dubois, R
    Dumora, D
    Edmonds, Y
    Farnier, C
    Favuzzi, C
    Fegan, S J
    Focke, W B
    Frailis, M
    Freire, P C C
    Fukazawa, Y
    Funk, S
    Fusco, P
    Gargano, F
    Gasparrini, D
    Gehrels, N
    Germani, S
    Giebels, B
    Giglietto, N
    Giordano, F
    Glanzman, T
    Godfrey, G
    Grenier, I A
    Grondin, M H
    Grove, J E
    Guillemot, L
    Guiriec, S
    Hanabata, Y
    Harding, A K
    Hayashida, M
    Hays, E
    Hobbs, G
    Hughes, R E
    Jóhannesson, G
    Johnson, A S
    Johnson, R P
    Johnson, T J
    Johnson, W N
    Johnston, S
    Kamae, T
    Katagiri, H
    Kataoka, J
    Kawai, N
    Kerr, M
    Knödlseder, J
    Kocian, M L
    Kramer, M
    Kuss, M
    Lande, J
    Latronico, L
    Lemoine-Goumard, M
    Longo, F
    Loparco, F
    Lott, B
    Lovellette, M N
    Lubrano, P
    Madejski, G M
    Makeev, A
    Manchester, R N
    Marelli, M
    Mazziotta, M N
    McConville, W
    McEnery, J E
    McLaughlin, M A
    Meurer, C
    Michelson, P F
    Mitthumsiri, W
    Mizuno, T
    Moiseev, A A
    Monte, C
    Monzani, M E
    Morselli, A
    Moskalenko, I V
    Murgia, S
    Nolan, P L
    Norris, J P
    Nuss, E
    Ohsugi, T
    Omodei, N
    Orlando, E
    Ormes, J F
    Paneque, D
    Panetta, J H
    Parent, D
    Pelassa, V
    Pepe, M
    Pesce-Rollins, M
    Piron, F
    Porter, T A
    Rainò, S
    Rando, R
    Ransom, S M
    Ray, P S
    Razzano, M
    Rea, N
    Reimer, A
    Reimer, O
    Reposeur, T
    Ritz, S
    Rochester, L S
    Rodriguez, A Y
    Romani, R W
    Roth, M
    Ryde, F
    Sadrozinski, H F W
    Sanchez, D
    Sander, A
    Saz Parkinson, P M
    Scargle, J D
    Schalk, T L
    Sgrò, C
    Siskind, E J
    Smith, D A
    Smith, P D
    Spandre, G
    Spinelli, P
    Stappers, B W
    Starck, J L
    Striani, E
    Strickman, M S
    Suson, D J
    Tajima, H
    Takahashi, H
    Tanaka, T
    Thayer, J B
    Thayer, J G
    Theureau, G
    Thompson, D J
    Thorsett, S E
    Tibaldo, L
    Torres, D F
    Tosti, G
    Tramacere, A
    Uchiyama, Y
    Usher, T L
    Van Etten, A
    Vasileiou, V
    Venter, C
    Vilchez, N
    Vitale, V
    Waite, A P
    Wallace, E
    Wang, P
    Watters, K
    Webb, N
    Weltevrede, P
    Winer, B L
    Wood, K S
    Ylinen, T
    Ziegler, M
    A population of gamma-ray millisecond pulsars seen with the Fermi Large Area Telescope.2009Ingår i: Science (New York, N.Y.), ISSN 1095-9203, Vol. 325, nr 5942, s. 848-52Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. A second life can occur for neutron stars in binary systems. They can acquire mass and angular momentum from their companions, to be spun up to millisecond periods and begin radiating again. We searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars (MSPs) outside of globular clusters, using rotation parameters from radio telescopes. Strong gamma-ray pulsations were detected for eight MSPs. The gamma-ray pulse profiles and spectral properties resemble those of young gamma-ray pulsars. The basic emission mechanism seems to be the same for MSPs and young pulsars, with the emission originating in regions far from the neutron star surface.

  • 7. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Caliandro, G. A.
    Cameron, R. A.
    Camilo, F.
    Caraveo, P. A.
    Casandjian, J. M.
    Cecchi, C.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cognard, I.
    Cohen-Tanugi, J.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    de Angelis, A.
    de Palma, F.
    Dormody, M.
    Silva, E. do Couto e.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Frailis, M.
    Freire, P. C. C.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Halpern, J.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Hobbs, G.
    Hughes, R. E.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, T. J.
    Johnson, W. N.
    Johnston, S.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knödlseder, J.
    Kocian, M. L.
    Kramer, M.
    Kuehn, F.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Lyne, A. G.
    Makeev, A.
    Manchester, R. N.
    Marelli, M.
    Mazziotta, M. N.
    McEnery, J. E.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Noutsos, A.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Ransom, S. M.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Sgrò, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Stappers, B. W.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Theureau, G.
    Thompson, D. J.
    Thorsett, S. E.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Uchiyama, Y.
    Usher, T. L.
    Van Etten, A.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Wang, N.
    Watters, K.
    Weltevrede, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    Fermi Large Area Telescope Detection of Pulsed γ-rays from the Vela-like Pulsars PSR J1048–5832 and PSR J2229+61142009Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 706, nr 2, s. 1331-1340Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the detection of γ-ray pulsations (>=0.1 GeV) from PSR J2229+6114 and PSR J1048–5832, the latter having been detected as a low-significance pulsar by EGRET. Data in the γ-ray band were acquired by the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope, while the radio rotational ephemerides used to fold the γ-ray light curves were obtained using the Green Bank Telescope, the Lovell telescope at Jodrell Bank, and the Parkes Telescope. The two young radio pulsars, located within the error circles of the previously unidentified EGRET sources 3EG J1048–5840 and 3EG J2227+6122, present spin-down characteristics similar to the Vela pulsar. PSR J1048–5832 shows two sharp peaks at phases 0.15 ± 0.01 and 0.57 ± 0.01 relative to the radio pulse confirming the EGRET light curve, while PSR J2229+6114 presents a very broad peak at phase 0.49 ± 0.01. The γ-ray spectra above 0.1 GeV of both pulsars are fit with power laws having exponential cutoffs near 3 GeV, leading to integral photon fluxes of (2.19 ± 0.22 ± 0.32) × 10–7 cm–2 s–1 for PSR J1048–5832 and (3.77 ± 0.22 ± 0.44) × 10–7 cm–2 s–1 for PSR J2229+6114. The first uncertainty is statistical and the second is systematic. PSR J1048–5832 is one of the two LAT sources which were entangled together as 3EG J1048–5840. These detections add to the growing number of young γ-ray pulsars that make up the dominant population of GeV γ-ray sources in the Galactic plane.

  • 8. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Çelik, Ö.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cutini, S.
    de Angelis, A.
    de Palma, F.
    Di Bernardo, G.
    Silva, E. do Couto e.
    Drell, P. S.
    Drlica-Wagner, A.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Finke, J.
    Focke, W. B.
    Fortin, P.
    Foschini, L.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giavitto, G.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Hayashida, M.
    Hays, E.
    Horan, D.
    Hughes, R. E.
    Jackson, M. S.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knödlseder, J.
    Kocian, M. L.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Reyes, L. C.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Schalk, T. L.
    Sellerholm, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Sgrò, C.
    Shaw, M. S.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Tanaka, Y.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    Fermi Observations of TeV-Selected Active Galactic Nuclei2009Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 707, nr 2, s. 1310-1333Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on observations of TeV-selected active galactic nuclei (AGNs) made during the first 5.5 months of observations with the Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope (Fermi). In total, 96 AGNs were selected for study, each being either (1) a source detected at TeV energies (28 sources) or (2) an object that has been studied with TeV instruments and for which an upper limit has been reported (68 objects). The Fermi observations show clear detections of 38 of these TeV-selected objects, of which 21 are joint GeV-TeV sources, and 29 were not in the third EGRET catalog. For each of the 38 Fermi-detected sources, spectra and light curves are presented. Most can be described with a power law of spectral index harder than 2.0, with a spectral break generally required to accommodate the TeV measurements. Based on an extrapolation of the Fermi spectrum, we identify sources, not previously detected at TeV energies, which are promising targets for TeV instruments. Evidence for systematic evolution of the γ-ray spectrum with redshift is presented and discussed in the context of interaction with the extragalactic background light.

  • 9. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Çelik, Ö.
    Charles, E.
    Chaty, S.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Corbel, S.
    Corbet, R.
    Cutini, S.
    Dermer, C. D.
    de Angelis, A.
    de Luca, A.
    de Palma, F.
    Digel, S. W.
    Dormody, M.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dubus, G.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Hill, A. B.
    Hughes, R. E.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knödlseder, J.
    Kocian, M. L.
    Kuehn, F.
    Kuss, M.
    Lande, J.
    Larsson, S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Latronico, L.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Marelli, M.
    Mazziotta, M. N.
    McEnery, J. E.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Nuss, E.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Ray, P. S.
    Razzano, M.
    Rea, N.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Sgrò, C.
    Shaw, M. S.
    Sierpowska-Bartosik, A.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Striani, E.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    Fermi LAT Observations of LS I +61°303: First Detection of an Orbital Modulation in GeV Gamma Rays2009Ingår i: Astrophysical Journal Letters, Vol. 701, nr 2, s. L123-L128Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This Letter presents the first results from the observations of LS I +61°303 using Large Area Telescope data from the Fermi Gamma-Ray Space Telescope between 2008 August and 2009 March. Our results indicate variability that is consistent with the binary period, with the emission being modulated at 26.6 ± 0.5 days. This constitutes the first detection of orbital periodicity in high-energy gamma rays (20 MeV-100 GeV, HE). The light curve is characterized by a broad peak after periastron, as well as a smaller peak just before apastron. The spectrum is best represented by a power law with an exponential cutoff, yielding an overall flux above 100 MeV of 0.82 ± 0.03(stat) ± 0.07(syst) 10-6 ph cm-2 s-1, with a cutoff at 6.3 ± 1.1(stat) ± 0.4(syst) GeV and photon index Γ = 2.21 ± 0.04(stat) ± 0.06(syst). There is no significant spectral change with orbital phase. The phase of maximum emission, close to periastron, hints at inverse Compton scattering as the main radiation mechanism. However, previous very high-energy gamma ray (>100 GeV, VHE) observations by MAGIC and VERITAS show peak emission close to apastron. This and the energy cutoff seen with Fermi suggest that the link between HE and VHE gamma rays is nontrivial.

  • 10. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Çelik, Ö.
    Chaty, S.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Corbel, S.
    Corbet, R.
    Cutini, S.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    Silva, E. do Couto e.
    Drell, P. S.
    Dubois, R.
    Dubus, G.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Hill, A. B.
    Horan, D.
    Hughes, R. E.
    Jackson, M. S.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knödlseder, J.
    Kocian, M. L.
    Kuehn, F.
    Kuss, M.
    Lande, J.
    Larsson, S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Marelli, M.
    Mazziotta, M. N.
    McEnery, J. E.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Ray, P. S.
    Razzano, M.
    Rea, N.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Sgrò, C.
    Sierpowska-Bartosik, A.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Tanaka, Y.
    Thayer, J. B.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Venter, C.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wallace, E.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    Fermi/LAT observations of LS 50392009Ingår i: Astrophysical Journal Letters, ISSN 05717248, Vol. 706, nr 1, s. L56-L61Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The first results from observations of the high-mass X-ray binary LS 5039 using the Fermi Gamma-ray Space Telescope data between 2008 August and 2009 June are presented. Our results indicate variability that is consistent with the binary period, with the emission being modulated with a period of 3.903 ± 0.005 days; the first detection of this modulation at GeV energies. The light curve is characterized by a broad peak around superior conjunction in agreement with inverse Compton scattering models. The spectrum is represented by a power law with an exponential cutoff, yielding an overall flux (100 MeV-300 GeV) of 4.9 ± 0.5(stat) ± 1.8(syst) ×10–7 photon cm–2 s–1, with a cutoff at 2.1 ± 0.3(stat) ± 1.1(syst) GeV and photon index Γ = 1.9 ± 0.1(stat) ± 0.3(syst). The spectrum is observed to vary with orbital phase, specifically between inferior and superior conjunction. We suggest that the presence of a cutoff in the spectrum may be indicative of magnetospheric emission similar to the emission seen in many pulsars by Fermi.

  • 11. Abdo, A A
    et al.
    Ackermann, M
    Ajello, M
    Atwood, W B
    Axelsson, M
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L
    Ballet, J
    Barbiellini, G
    Bastieri, D
    Baughman, B M
    Bechtol, K
    Bellazzini, R
    Berenji, B
    Blandford, R D
    Bloom, E D
    Bonamente, E
    Borgland, A W
    Bregeon, J
    Brez, A
    Brigida, M
    Bruel, P
    Burnett, T H
    Caliandro, G A
    Cameron, R A
    Caraveo, P A
    Casandjian, J M
    Cecchi, C
    Celik, O
    Charles, E
    Chaty, S
    Chekhtman, A
    Cheung, C C
    Chiang, J
    Ciprini, S
    Claus, R
    Cohen-Tanugi, J
    Conrad, J
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cutini, S
    Dermer, C D
    de Palma, F
    Digel, S W
    Dormody, M
    do Couto e Silva, E
    Drell, P S
    Dubois, R
    Dumora, D
    Farnier, C
    Favuzzi, C
    Fegan, S J
    Focke, W B
    Frailis, M
    Fukazawa, Y
    Fusco, P
    Gargano, F
    Gasparrini, D
    Gehrels, N
    Germani, S
    Giebels, B
    Giglietto, N
    Giordano, F
    Glanzman, T
    Godfrey, G
    Grenier, I A
    Grove, J E
    Guillemot, L
    Guiriec, S
    Hanabata, Y
    Harding, A K
    Hayashida, M
    Hays, E
    Horan, D
    Hughes, R E
    Jóhannesson, G
    Johnson, A S
    Johnson, R P
    Johnson, T J
    Johnson, W N
    Kamae, T
    Katagiri, H
    Kawai, N
    Kerr, M
    Knödlseder, J
    Kuehn, F
    Kuss, M
    Lande, J
    Latronico, L
    Lemoine-Goumard, M
    Longo, F
    Loparco, F
    Lott, B
    Lovellette, M N
    Lubrano, P
    Makeev, A
    Mazziotta, M N
    McConville, W
    McEnery, J E
    Meurer, C
    Michelson, P F
    Mitthumsiri, W
    Mizuno, T
    Moiseev, A A
    Monte, C
    Monzani, M E
    Morselli, A
    Moskalenko, I V
    Murgia, S
    Nolan, P L
    Norris, J P
    Nuss, E
    Ohsugi, T
    Omodei, N
    Orlando, E
    Ormes, J F
    Paneque, D
    Panetta, J H
    Parent, D
    Pelassa, V
    Pepe, M
    Pierbattista, M
    Piron, F
    Porter, T A
    Rainò, S
    Rando, R
    Razzano, M
    Rea, N
    Reimer, A
    Reimer, O
    Reposeur, T
    Ritz, S
    Rochester, L S
    Rodriguez, A Y
    Romani, R W
    Roth, M
    Ryde, F
    Sadrozinski, H F-W
    Sanchez, D
    Sander, A
    Saz Parkinson, P M
    Sgrò, C
    Smith, D A
    Smith, P D
    Spandre, G
    Spinelli, P
    Starck, J-L
    Strickman, M S
    Suson, D J
    Tajima, H
    Takahashi, H
    Tanaka, T
    Thayer, J B
    Thayer, J G
    Thompson, D J
    Tibaldo, L
    Torres, D F
    Tosti, G
    Tramacere, A
    Uchiyama, Y
    Usher, T L
    Vasileiou, V
    Vilchez, N
    Vitale, V
    Wang, P
    Webb, N
    Winer, B L
    Wood, K S
    Ylinen, T
    Ziegler, M
    Detection of high-energy gamma-ray emission from the globular cluster 47 Tucanae with Fermi.2009Ingår i: Science (New York, N.Y.), ISSN 1095-9203, Vol. 325, nr 5942, s. 845-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the detection of gamma-ray emissions above 200 megaelectron volts at a significance level of 17sigma from the globular cluster 47 Tucanae, using data obtained with the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. Globular clusters are expected to emit gamma rays because of the large populations of millisecond pulsars that they contain. The spectral shape of 47 Tucanae is consistent with gamma-ray emission from a population of millisecond pulsars. The observed gamma-ray luminosity implies an upper limit of 60 millisecond pulsars present in 47 Tucanae.

  • 12. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Carlson, P.
    Casandjian, J. M.
    Cecchi, C.
    Çelik, Ö.
    Chekhtman, A.
    Cheung, C. C.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cutini, S.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    Silva, E. do Couto e.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Hughes, R. E.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kawai, N.
    Kerr, M.
    Knödlseder, J.
    Kocian, M. L.
    Kuehn, F.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Makeev, A.
    Mazziotta, M. N.
    McEnery, J. E.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Pohl, M.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Schalk, T. L.
    Sellerholm, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Sgrò, C.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J.-L.
    Stecker, F. W.
    Strickman, M. S.
    Strong, A. W.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    Fermi LAT Observation of Diffuse Gamma Rays Produced Through Interactions Between Local Interstellar Matter and High-energy Cosmic Rays2009Ingår i: Astrophysical Journal Supplement Series, ISSN 0067-0049, E-ISSN 1538-4365, Vol. 703, nr 2, s. 1249-1256Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Observations by the Large Area Telescope (LAT) on the Fermi mission of diffuse γ-rays in a mid-latitude region in the third quadrant (Galactic longitude l from 200° to 260° and latitude |b| from 22° to 60°) are reported. The region contains no known large molecular cloud and most of the atomic hydrogen is within 1 kpc of the solar system. The contributions of γ-ray point sources and inverse Compton scattering are estimated and subtracted. The residual γ-ray intensity exhibits a linear correlation with the atomic gas column density in energy from 100 MeV to 10 GeV. The measured integrated γ-ray emissivity is (1.63 ± 0.05) × 10-26 photons s-1sr-1 H-atom-1 and (0.66 ± 0.02) × 10-26 photons s-1sr-1 H-atom-1 above 100 MeV and above 300 MeV, respectively, with an additional systematic error of ~10%. The differential emissivity from 100 MeV to 10 GeV agrees with calculations based on cosmic ray spectra consistent with those directly measured, at the 10% level. The results obtained indicate that cosmic ray nuclei spectra within 1 kpc from the solar system in regions studied are close to the local interstellar spectra inferred from direct measurements at the Earth within ~10%.

  • 13. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Cannon, A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Çelik, Ö.
    Charles, E.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Colafrancesco, S.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Costamante, L.
    Cutini, S.
    Davis, D. S.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    Donato, D.
    Silva, E. do Couto e.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Edmonds, Y.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Finke, J.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Georganopoulos, M.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Horan, D.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knödlseder, J.
    Kocian, M. L.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sambruna, R.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Sgrò, C.
    Shaw, M. S.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Tanaka, T.
    Taylor, G. B.
    Thayer, J. B.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    Harris, D. E.
    Massaro, F.
    Stawarz, Ł.
    Fermi Large Area Telescope Gamma-Ray Detection of the Radio Galaxy M872009Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 707, nr 1, s. 55-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the Fermi Large Area Telescope (LAT) discovery of high-energy (MeV/GeV) γ-ray emission positionally consistent with the center of the radio galaxy M87, at a source significance of over 10σ in 10 months of all-sky survey data. Following the detections of Cen A and Per A, this makes M87 the third radio galaxy seen with the LAT. The faint point-like γ-ray source has a >100 MeV flux of 2.45 (±0.63) × 10–8 photons cm–2 s–1 (photon index = 2.26 ± 0.13) with no significant variability detected within the LAT observation. This flux is comparable with the previous EGRET upper limit (<2.18 × 10–8 photons cm–2 s–1, 2σ), thus there is no evidence for a significant MeV/GeV flare on decade timescales. Contemporaneous Chandra and Very Long Baseline Array data indicate low activity in the unresolved X-ray and radio core relative to previous observations, suggesting M87 is in a quiescent overall level over the first year of Fermi-LAT observations. The LAT γ-ray spectrum is modeled as synchrotron self-Compton (SSC) emission from the electron population producing the radio-to-X-ray emission in the core. The resultant SSC spectrum extrapolates smoothly from the LAT band to the historical-minimum TeV emission. Alternative models for the core and possible contributions from the kiloparsec-scale jet in M87 are considered, and cannot be excluded.

  • 14. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Atwood, W. B.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, Oe
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cutini, S.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M. -H
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Harding, A. K.
    Hartman, R. C.
    Hayashida, M.
    Hays, E.
    Healey, S. E.
    Horan, D.
    Hughes, R. E.
    Jackson, M. S.
    Johannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Meurer, C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Persic, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F. -W
    Sanchez, D.
    Sander, A.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Sgro, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Villata, M.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    SPECTRAL PROPERTIES OF BRIGHT FERMI-DETECTED BLAZARS IN THE GAMMA-RAY BAND2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 710, nr 2, s. 1271-1285Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The gamma-ray energy spectra of bright blazars of the LAT Bright AGN Sample LBAS) are investigated using Fermi-LAT data. Spectral properties hardness, curvature, and variability) established using a data set accumulated over 6 months of operation are presented and discussed for different blazar classes and subclasses: flat spectrum radio quasars (FSRQs), low-synchrotron peaked BLLacs (LSP-BLLacs), intermediate-synchrotron peaked BLLacs (ISP-BLLacs), and high-synchrotron peaked BLLacs (HSP-BLLacs). The distribution of photon index G, obtained from a power-law fit above 100 MeV) is found to correlate strongly with blazar subclass. The change in spectral index from that averaged over the 6 months observing period is < 0.2-0.3 when the flux varies by about an order of magnitude, with a tendency toward harder spectra when the flux is brighter for FSRQs and LSP-BLLacs. A strong departure from a single power-law spectrum appears to be a common feature for FSRQs. This feature is also present for some high-luminosity LSP-BLLacs, and a small number of ISP-BLLacs. It is absent in all LBAS HSP-BLLacs. For 3C 454.3 and AO 0235+164, the two brightest FSRQ source and LSP-BLLac source, respectively, a broken power law (BPL) gives the most acceptable of power law, BPL, and curved forms. The consequences of these findings are discussed.

  • 15. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Atwood, W. B.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, Oe
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    do Couto e Silva, E.
    Drell, P. S.
    Drlica-Wagner, A.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Foschini, L.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M. -H
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Hughes, R. E.
    Johannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knoedlseder, J.
    Kocian, M. L.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Meurer, C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F. -W
    Sander, A.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Sellerholm, Alexander
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Sgro, C.
    Shaw, M. S.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Strickman, M. S.
    Strong, A. W.
    Suson, D. J.
    Takahashi, H.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Tibolla, O.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    DETECTION OF GAMMA-RAY EMISSION FROM THE STARBURST GALAXIES M82 AND NGC 253 WITH THE LARGE AREA TELESCOPE ON FERMI2010Ingår i: The Astrophysical Journal Letters, ISSN 2041-8205, Vol. 709, nr 2, s. l152-L157Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the detection of high-energy gamma-ray emission from two starburst galaxies using data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. Steady point-like emission above 200 MeV has been detected at significance levels of 6.8 sigma and 4.8 sigma, respectively, from sources positionally coincident with locations of the starburst galaxies M82 and NGC 253. The total fluxes of the sources are consistent with gamma-ray emission originating from the interaction of cosmic rays with local interstellar gas and radiation fields and constitute evidence for a link between massive star formation and gamma-ray emission in star-forming galaxies.

  • 16. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Atwood, W. B.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, Oe.
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cutini, S.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M. -H
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Horan, D.
    Hughes, R. E.
    Johannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knoedlseder, J.
    Kocian, M. L.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Meurer, C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F. -W
    Sanchez, D.
    Sander, A.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Sgro, C.
    Shaw, M. S.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Strickman, M. S.
    Suson, D. J.
    Takahashi, H.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    FERMI OBSERVATIONS OF THE VERY HARD GAMMA-RAY BLAZAR PG 1553+1132010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 708, nr 2, s. 1310-1320Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the observations of PG 1553+113 during the first similar to 200 days of Fermi Gamma-ray Space Telescope science operations, from 2008 August 4 to 2009 February 22 (MJD 54682.7-54884.2). This is the first detailed study of PG 1553+113 in the GeV gamma-ray regime and it allows us to fill a gap of three decades in energy in its spectral energy distribution (SED). We find PG 1553+113 to be a steady source with a hard spectrum that is best fit by a simple power law in the Fermi energy band. We combine the Fermi data with archival radio, optical, X-ray, and very high energy (VHE) gamma-ray data to model its broadband SED and find that a simple, one-zone synchrotron self-Compton model provides a reasonable fit. PG 1553+113 has the softest VHE spectrum of all sources detected in that regime and, out of those with significant detections across the Fermi energy bandpass so far, the hardest spectrum in that energy regime. Thus, it has the largest spectral break of any gamma-ray source studied to date, which could be due to the absorption of the intrinsic gamma-ray spectrum by the extragalactic background light (EBL). Assuming this to be the case, we selected a model with a low level of EBL and used it to absorb the power-law spectrum from PG 1553+113 measured with Fermi (200 MeV-157 GeV) to find the redshift, which gave the best fit to the measured VHE data (90 GeV-1.1 TeV) for this parameterization of the EBL. We show that this redshift can be considered an upper limit on the distance to PG 1553+113.

  • 17. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Çelik, Ö.
    Celotti, A.
    Chekhtman, A.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Collmar, W.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Costamante, L.
    Cutini, S.
    de Angelis, A.
    de Palma, F.
    Silva, E. Do Couto e.
    Drell, P. S.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Fortin, P.
    Foschini, L.
    Frailis, M.
    Fuhrmann, L.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gehrels, N.
    Germani, S.
    Giglietto, N.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Hays, E.
    Hughes, R. E.
    Jackson, M. S.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kadler, M.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knödlseder, J.
    Kocian, M. L.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Max-Moerbeck, W.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    McGlynn, S.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Nestoras, I.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Paneque, D.
    Parent, D.
    Pavlidou, V.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Razzano, M.
    Readhead, A.
    Reimer, O.
    Reposeur, T.
    Richards, J. L.
    Rodriguez, A. Y.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Sgrò, C.
    Shaw, M. S.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Strickman, M. S.
    Suson, D. J.
    Tagliaferri, G.
    Tajima, H.
    Takahashi, H.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Tibolla, O.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Wehrle, A. E.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Zensus, J. A.
    Ziegler, M.
    The Fermi/LAT Collaboration,
    Angelakis, E.
    Bailyn, C.
    Bignall, H.
    Blanchard, J.
    Bonning, E. W.
    Buxton, M.
    Canterna, R.
    Carramiñana, A.
    Carrasco, L.
    Colomer, F.
    Doi, A.
    Ghisellini, G.
    Hauser, M.
    Hong, X.
    Isler, J.
    Kino, M.
    Kovalev, Y. Y.
    Kovalev, Yu. A.
    Krichbaum, T. P.
    Kutyrev, A.
    Lahteenmaki, A.
    van Langevelde, H. J.
    Lister, M. L.
    Macomb, D.
    Maraschi, L.
    Marchili, N.
    Nagai, H.
    Paragi, Z.
    Phillips, C.
    Pushkarev, A. B.
    Recillas, E.
    Roming, P.
    Sekido, M.
    Stark, M. A.
    Szomoru, A.
    Tammi, J.
    Tavecchio, F.
    Tornikoski, M.
    Tzioumis, A. K.
    Urry, C. M.
    Wagner, S.
    Multiwavelength Monitoring of the Enigmatic Narrow-Line Seyfert 1 PMN J0948+0022 in 2009 March-July2009Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 707, nr 1, s. 727-737Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Following the recent discovery of γ rays from the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022 (z = 0.5846), we started a multiwavelength campaign from radio to γ rays, which was carried out between the end of 2009 March and the beginning of July. The source displayed activity at all the observed wavelengths: a general decreasing trend from optical to γ-ray frequencies was followed by an increase of radio emission after less than two months from the peak of the γ-ray emission. The largest flux change, about a factor of about 4, occurred in the X-ray band. The smallest was at ultraviolet and near-infrared frequencies, where the rate of the detected photons dropped by a factor 1.6-1.9. At optical wavelengths, where the sampling rate was the highest, it was possible to observe day scale variability, with flux variations up to a factor of about 3. The behavior of PMN J0948+0022 observed in this campaign and the calculated power carried out by its jet in the form of protons, electrons, radiation, and magnetic field are quite similar to that of blazars, specifically of flat-spectrum radio quasars. These results confirm the idea that radio-loud narrow-line Seyfert 1 galaxies host relativistic jets with power similar to that of average blazars.

  • 18. Abdo, A. A.
    et al.
    Ackermann, M.
    Asano, K.
    Atwood, W. B.
    Axelsson, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Band, D. L.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bhat, P. N.
    Bissaldi, E.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Briggs, M. S.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cecchi, C.
    Chaplin, V.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Connaughton, V.
    Conrad, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cutini, S.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    Silva, E. do Couto e.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Focke, W. B.
    Frailis, M.
    Fukazawa, Y.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Gibby, L.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Goldstein, A.
    Granot, J.
    Grenier, I. A.
    Grondin, M.-H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Hughes, R. E.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knödlseder, J.
    Kocevski, D.
    Komin, N.
    Kouveliotou, C.
    Kuehn, F.
    Kuss, M.
    Latronico, L.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Makeev, A.
    Mazziotta, M. N.
    McBreen, S.
    McEnery, J. E.
    McGlynn, S.
    Meegan, C.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Monte, C.
    Monzani, M. E.
    Moretti, E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paciesas, W. S.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Preece, R.
    Rainò, S.
    Rando, R.
    Razzano, M.
    Razzaque, S.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F.-W.
    Sanchez, D.
    Sander, A.
    Saz Parkinson, P. M.
    Scargle, J. D.
    Sgrò, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Stamatikos, M.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    van der Horst, A. J.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    von Kienlin, A.
    Waite, A. P.
    Wang, P.
    Wilson-Hodge, C.
    Winer, B. L.
    Wood, K. S.
    Ylinen, T.
    Ziegler, M.
    Fermi Observations of High-energy Gamma-ray Emission from GRB 080825C2009Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 707, nr 1, s. 580-592Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Fermi Gamma-ray Space Telescope has opened a new high-energy window in the study of gamma-ray bursts (GRBs). Here we present a thorough analysis of GRB 080825C, which triggered the Fermi Gamma-ray Burst Monitor (GBM), and was the first firm detection of a GRB by the Fermi Large Area Telescope (LAT). We discuss the LAT event selections, background estimation, significance calculations, and localization for Fermi GRBs in general and GRB 080825C in particular. We show the results of temporal and time-resolved spectral analysis of the GBM and LAT data. We also present some theoretical interpretation of GRB 080825C observations as well as some common features observed in other LAT GRBs.

  • 19. Acero, F.
    et al.
    Ackermann, M.
    Ajello, M.
    Albert, A.
    Atwood, W. B.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Belfiore, A.
    Bellazzini, R.
    Bissaldi, E.
    Blandford, R. D.
    Bloom, E. D.
    Bogart, J. R.
    Bonino, R.
    Bottacini, E.
    Bregeon, J.
    Britto, R. J.
    Bruel, P.
    Buehler, R.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caputo, R.
    Caragiulo, M.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Charles, E.
    Chaves, R. C. G.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Chiaro, G.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Conrad, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC). Royal Swedish Academy of Science, Sweden.
    Cutini, S.
    D'Ammando, F.
    de Angelis, A.
    DeKlotz, M.
    de Palma, F.
    Desiante, R.
    Digel, S. W.
    Di Venere, L.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Finke, J.
    Franckowiak, A.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M. -H.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hadasch, D.
    Harding, A. K.
    Hays, E.
    Hewitt, J. W.
    Hill, A. B.
    Horan, D.
    Iafrate, G.
    Jogler, T.
    Johannesson, G.
    Johnson, R. P.
    Johnson, A. S.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Kataoka, J.
    Katsuta, J.
    Kuss, M.
    La Mura, G.
    Landriu, D.
    Larsson, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Latronico, L.
    Lemoine-Goumard, M.
    Li, J.
    Li, L.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Massaro, F.
    Mayer, M.
    Mazziotta, M. N.
    McEnery, J. E.
    Michelson, P. F.
    Mirabal, N.
    Mizuno, T.
    Moiseev, A. A.
    Mongelli, M.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orienti, M.
    Orlando, E.
    Ormes, J. F.
    Paneque, D.
    Panetta, J. H.
    Perkins, J. S.
    Pesce-Rollins, M.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Racusin, J. L.
    Rando, R.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Rochester, L. S.
    Romani, R. W.
    Salvetti, D.
    Sanchez-Coude, Miguel
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Parkinson, P. M. Saz
    Schulz, A.
    Siskind, E. J.
    Smith, D. A.
    Spada, F.
    Spandre, G.
    Spinelli, P.
    Stephens, T. E.
    Strong, A. W.
    Suson, D. J.
    Takahashi, H.
    Takahashi, T.
    Tanaka, Y.
    Thayer, J. G.
    Thayer, J. B.
    Thompson, D. J.
    Tibaldo, L.
    Tibolla, O.
    Torres, D. F.
    Torresi, E.
    Tosti, G.
    Troja, E.
    Van Klaveren, B.
    Vianello, G.
    Winer, B. L.
    Wood, K. S.
    Wood, M.
    Zimmer, Stephan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    FERMI LARGE AREA TELESCOPE THIRD SOURCE CATALOG2015Ingår i: Astrophysical Journal Supplement Series, ISSN 0067-0049, E-ISSN 1538-4365, Vol. 218, nr 2, artikel-id 23Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the third Fermi Large Area Telescope (LAT) source catalog (3FGL) of sources in the 100 MeV-300 GeV range. Based on the first 4 yr of science data from the Fermi Gamma-ray Space Telescope mission, it is the deepest yet in this energy range. Relative to the Second Fermi LAT catalog, the 3FGL catalog incorporates twice as much data, as well as a number of analysis improvements, including improved calibrations at the event reconstruction level, an updated model for Galactic diffuse.-ray emission, a refined procedure for source detection, and improved methods for associating LAT sources with potential counterparts at other wavelengths. The 3FGL catalog includes 3033 sources above 4 sigma significance, with source location regions, spectral properties, and monthly light curves for each. Of these, 78 are flagged as potentially being due to imperfections in the model for Galactic diffuse emission. Twenty-five sources are modeled explicitly as spatially extended, and overall 238 sources are considered as identified based on angular extent or correlated variability (periodic or otherwise) observed at other wavelengths. For 1010 sources we have not found plausible counterparts at other wavelengths. More than 1100 of the identified or associated sources are active galaxies of the blazar class; several other classes of non-blazar active galaxies are also represented in the 3FGL. Pulsars represent the largest Galactic source class. From source counts of Galactic sources we estimate that the contribution of unresolved sources to the Galactic diffuse emission is similar to 3% at 1 GeV.

  • 20. Ackermann, M.
    et al.
    Ajello, M.
    Albert, A.
    Allafort, A.
    Atwood, W. B.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC). Royal Institute of Technology (KTH), Sweden.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Bissaldi, E.
    Blandford, R. D.
    Bloom, E. D.
    Bogart, J. R.
    Bonamente, E.
    Borgland, A. W.
    Bottacini, E.
    Bouvier, A.
    Brandt, T. J.
    Bregeon, J.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, O.
    Charles, E.
    Chaves, R. C. G.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Corbet, R.
    Cutini, S.
    D'Ammando, F.
    Davis, D. S.
    de Angelis, A.
    DeKlotz, M.
    de Palma, F.
    Dermer, C. D.
    Digel, S. W.
    do Couto e Silva, E.
    Drell, P. S.
    Drlica-Wagner, A.
    Dubois, R.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Focke, W. B.
    Fortin, P.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grove, J. E.
    Guiriec, S.
    Hadasch, D.
    Hayashida, M.
    Hays, E.
    Horan, D.
    Hou, X.
    Hughes, R. E.
    Jackson, M. S.
    Jogler, T.
    Johannesson, G.
    Johnson, R. P.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kerr, M.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Larsson, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Latronico, L.
    Lavalley, C.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Mehault, J.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Naumann-Godo, M.
    Nemmen, R.
    Nishino, S.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orienti, M.
    Orlando, E.
    Ormes, J. F.
    Paneque, D.
    Panetta, J. H.
    Perkins, J. S.
    Pesce-Rollins, M.
    Pierbattista, M.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Racusin, J. L.
    Raino, S.
    Rando, R.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Reyes, L. C.
    Ritz, S.
    Rochester, L. S.
    Romoli, C.
    Roth, M.
    Sadrozinski, H. F. -W
    Sanchez, D. A.
    Parkinson, P. M. Saz
    Sbarra, C.
    Scargle, J. D.
    Sgro, C.
    Siegal-Gaskins, J.
    Siskind, E. J.
    Spandre, G.
    Spinelli, P.
    Stephens, T. E.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Tanaka, T.
    Thayer, J. G.
    Thayer, J. B.
    Thompson, D. J.
    Tibaldo, L.
    Tinivella, M.
    Tosti, G.
    Troja, E.
    Usher, T. L.
    Vandenbroucke, J.
    Van Klaveren, B.
    Vasileiou, V.
    Vianello, G.
    Vitale, V.
    Waite, A. P.
    Wallace, E.
    Winer, B. L.
    Wood, D. L.
    Wood, K. S.
    Wood, M.
    Yang, Zhaoyu
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Zimmer, Stephan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    THE FERMI LARGE AREA TELESCOPE ON ORBIT: EVENT CLASSIFICATION, INSTRUMENT RESPONSE FUNCTIONS, AND CALIBRATION2012Ingår i: Astrophysical Journal Supplement Series, ISSN 0067-0049, E-ISSN 1538-4365, Vol. 203, nr 1, artikel-id 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Fermi Large Area Telescope (Fermi-LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the energy range from 20 MeV to more than 300 GeV. During the first years of the mission, the LAT team has gained considerable insight into the in-flight performance of the instrument. Accordingly, we have updated the analysis used to reduce LAT data for public release as well as the instrument response functions (IRFs), the description of the instrument performance provided for data analysis. In this paper, we describe the effects that motivated these updates. Furthermore, we discuss how we originally derived IRFs from Monte Carlo simulations and later corrected those IRFs for discrepancies observed between flight and simulated data. We also give details of the validations performed using flight data and quantify the residual uncertainties in the IRFs. Finally, we describe techniques the LAT team has developed to propagate those uncertainties into estimates of the systematic errors on common measurements such as fluxes and spectra of astrophysical sources.

  • 21. Ackermann, M.
    et al.
    Ajello, M.
    Allafort, A.
    Antolini, E.
    Atwood, W. B.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC). Royal Institute of Technology (KTH), Sweden.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bottacini, E.
    Bouvier, A.
    Bregeon, J.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Charles, E.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Costamante, L.
    Cutini, S.
    de Angelis, A.
    de Palma, F.
    Dermer, C. D.
    Digel, S. W.
    Silva, E. do Couto e.
    Drell, P. S.
    Dubois, R.
    Escande, L.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Finke, J.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grove, J. E.
    Guiriec, S.
    Gustafsson, M.
    Hadasch, D.
    Hayashida, M.
    Hays, E.
    Healey, S. E.
    Horan, D.
    Hou, X.
    Hughes, R. E.
    Iafrate, G.
    Jóhannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Knödlseder, J.
    Kuss, M.
    Lande, J.
    Larsson, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Latronico, L.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Moretti, E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Naumann-Godo, M.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orienti, M.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Parent, D.
    Pesce-Rollins, M.
    Pierbattista, M.
    Piranomonte, S.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Rainò, S.
    Rando, R.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Ritz, S.
    Rochester, L. S.
    Romani, R. W.
    Roth, M.
    Sanchez, D. A.
    Sbarra, C.
    Scargle, J. D.
    Schalk, T. L.
    Sgrò, C.
    Shaw, M. S.
    Siskind, E. J.
    Spandre, G.
    Spinelli, P.
    Strong, A. W.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. G.
    Thayer, J. B.
    Thompson, D. J.
    Tibaldo, L.
    Tinivella, M.
    Torres, D. F.
    Tosti, G.
    Troja, E.
    Uchiyama, Y.
    Vandenbroucke, J.
    Vasileiou, V.
    Vianello, G.
    Vitale, V.
    Waite, A. P.
    Wallace, E.
    Wang, P.
    Winer, B. L.
    Wood, D. L.
    Wood, K. S.
    Zimmer, Stephan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    The Second Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope2011Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 743, nr 2, artikel-id 171Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years of scientific operation is presented. The second LAT AGN catalog (2LAC) includes 1017 γ-ray sources located at high Galactic latitudes (|b| > 10°) that are detected with a test statistic (TS) greater than 25 and associated statistically with AGNs. However, some of these are affected by analysis issues and some are associated with multiple AGNs. Consequently, we define a Clean Sample which includes 886 AGNs, comprising 395 BL Lacertae objects (BL Lac objects), 310 flat-spectrum radio quasars (FSRQs), 157 candidate blazars of unknown type (i.e., with broadband blazar characteristics but with no optical spectral measurement yet), 8 misaligned AGNs, 4 narrow-line Seyfert 1 (NLS1s), 10 AGNs of other types, and 2 starburst galaxies. Where possible, the blazars have been further classified based on their spectral energy distributions (SEDs) as archival radio, optical, and X-ray data permit. While almost all FSRQs have a synchrotron-peak frequency <1014 Hz, about half of the BL Lac objects have a synchrotron-peak frequency >1015 Hz. The 2LAC represents a significant improvement relative to the first LAT AGN catalog (1LAC), with 52% more associated sources. The full characterization of the newly detected sources will require more broadband data. Various properties, such as γ-ray fluxes and photon power-law spectral indices, redshifts, γ-ray luminosities, variability, and archival radio luminosities and their correlations are presented and discussed for the different blazar classes. The general trends observed in 1LAC are confirmed.

  • 22. Ackermann, M.
    et al.
    Ajello, M.
    Asano, K.
    Atwood, W. B.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Bissaldi, E.
    Bonamente, E.
    Bregeon, J.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Burgess, J. Michael
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Cecchi, C.
    Chaplin, V.
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Chiaro, G.
    Ciprini, S.
    Claus, R.
    Cleveland, W.
    Cohen-Tanugi, J.
    Collazzi, A.
    Cominsky, L. R.
    Connaughton, V.
    Conrad, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC). Royal Swedish Academy of Sciences, Sweden.
    Cutini, S.
    D'Ammando, F.
    de Angelis, A.
    DeKlotz, M.
    de Palma, F.
    Dermer, C. D.
    Desiante, R.
    Diekmann, A.
    Di Venere, L.
    Drell, P. S.
    Drlica-Wagner, A.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Finke, J.
    Fitzpatrick, G.
    Focke, W. B.
    Franckowiak, A.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gehrels, N.
    Germani, S.
    Gibby, M.
    Giglietto, N.
    Giles, M.
    Giordano, F.
    Giroletti, M.
    Godfrey, G.
    Granot, J.
    Grenier, I. A.
    Grove, J. E.
    Gruber, D.
    Guiriec, S.
    Hadasch, D.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Horan, D.
    Hughes, R. E.
    Inoue, Y.
    Jogler, T.
    Johannesson, G.
    Johnson, W. N.
    Kawano, T.
    Knoedlseder, J.
    Kocevski, D.
    Kuss, M.
    Lande, J.
    Larsson, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Latronico, L.
    Longo, F.
    Loparco, F.
    Lovellette, M. N.
    Lubrano, P.
    Mayer, M.
    Mazziotta, M. N.
    McEnery, J. E.
    Michelson, P. F.
    Mizuno, T.
    Moiseev, A. A.
    Monzani, M. E.
    Moretti, E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nemmen, R.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orienti, M.
    Paneque, D.
    Pelassa, V.
    Perkins, J. S.
    Pesce-Rollins, M.
    Petrosian, V.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Racusin, J. L.
    Raino, S.
    Rando, R.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Ritz, S.
    Roth, M.
    Ryde, F.
    Sartori, A.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Schulz, A.
    Sgro, C.
    Siskind, E. J.
    Sonbas, E.
    Spandre, G.
    Spinelli, P.
    Tajima, H.
    Takahashi, H.
    Thayer, J. G.
    Thayer, J. B.
    Thompson, D. J.
    Tibaldo, L.
    Tinivella, M.
    Torres, D. F.
    Tosti, G.
    Troja, E.
    Usher, T. L.
    Vandenbroucke, J.
    Vasileiou, V.
    Vianello, G.
    Vitale, V.
    Winer, B. L.
    Wood, K. S.
    Yamazaki, R.
    Younes, G.
    Yu, H. -F
    Zhu, S. J.
    Bhat, P. N.
    Briggs, M. S.
    Byrne, D.
    Foley, S.
    Goldstein, A.
    Jenke, P.
    Kippen, R. M.
    Kouveliotou, C.
    McBreen, S.
    Meegan, C.
    Paciesas, W. S.
    Preece, R.
    Rau, A.
    Tierney, D.
    van der Horst, A. J.
    von Kienlin, A.
    Wilson-Hodge, C.
    Xiong, S.
    Cusumano, G.
    La Parola, V.
    Cummings, J. R.
    Fermi-LAT Observations of the Gamma-Ray Burst GRB 130427A2014Ingår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 343, nr 6166, s. 42-47Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest gamma-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.

  • 23. Ackermann, M.
    et al.
    Ajello, M.
    Asano, K.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bhat, P. N.
    Bissaldi, E.
    Blandford, R. D.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Briggs, M. S.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cecchi, C.
    Celik, O.
    Chaplin, V.
    Charles, E.
    Chekhtman, A.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Connaughton, V.
    Conrad, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Cutini, S.
    Dermer, C. D.
    De Angelis, A.
    De Palma, F.
    Dingus, B. L.
    Silva, E. Do Couto E.
    Drell, P. S.
    Dubois, R.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Focke, W. B.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giglietto, N.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Goldstein, A.
    Granot, J.
    Greiner, J.
    Grenier, I. A.
    Grove, J. E.
    Guiriec, S.
    Hadasch, D.
    Hanabata, Y.
    Harding, A. K.
    Hayashi, K.
    Hayashida, M.
    Hays, E.
    Horan, D.
    Hughes, R. E.
    Itoh, R.
    Johannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kippen, R. M.
    Knoedlseder, J.
    Kocevski, D.
    Kouveliotou, C.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lee, S. -H
    Garde, Maja Llena
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Longo, F.
    Loparco, F.
    Lovellette, M. N.
    Lubrano, P.
    Makeev, A.
    Mazziotta, M. N.
    McBreen, S.
    McEnery, J. E.
    McGlynn, S.
    Meegan, C.
    Mehault, J.
    Meszaros, P.
    Michelson, P. F.
    Mizuno, T.
    Monte, C.
    Monzani, M. E.
    Moretti, E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakajima, H.
    Nakamori, T.
    Naumann-Godo, M.
    Nishino, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paciesas, W. S.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Petrosian, V.
    Piron, F.
    Porter, T. A.
    Preece, R.
    Racusin, J. L.
    Raino, S.
    Rando, R.
    Rau, A.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Reyes, L. C.
    Ripken, Joachim
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Ritz, S.
    Roth, M.
    Ryde, F.
    Sadrozinski, H. F. -W
    Sander, A.
    Scargle, J. D.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Tanaka, T.
    Tanaka, Y.
    Thayer, J. B.
    Thayer, J. G.
    Tibaldo, L.
    Tierney, D.
    Toma, K.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Uehara, T.
    Usher, T. L.
    Vandenbroucke, J.
    van der Horst, A. J.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    von Kienlin, A.
    Waite, A. P.
    Wang, P.
    Wilson-Hodge, C.
    Winer, B. L.
    Wood, K. S.
    Wu, X. F.
    Yamazaki, R.
    Yang, Zhaoyu
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Ylinen, T.
    Ziegler, M.
    DETECTION OF A SPECTRAL BREAK IN THE EXTRA HARD COMPONENT OF GRB 090926A2011Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 729, nr 2, s. 114-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on the observation of the bright, long gamma-ray burst, GRB 090926A, by the Gamma-ray Burst Monitor and Large Area Telescope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. GRB 090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in the light curve that is present in all detectors that see the burst, and this in turn suggests that there is a common region of emission across the entire Fermi energy range. In addition, while a separate high-energy power-law component has already been observed in other gamma-ray bursts, here we report for the first time the detection with good significance of a high-energy spectral break (or cutoff) in this power-law component around 1.4 GeV in the time-integrated spectrum. If the spectral break is caused by opacity to electron-positron pair production within the source, then this observation allows us to compute the bulk Lorentz factor for the outflow, rather than a lower limit.

  • 24. Ackermann, M.
    et al.
    Ajello, M.
    Asano, K.
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC). Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Bhat, P. N.
    Bissaldi, E.
    Bloom, E. D.
    Bonamente, E.
    Bonnell, J.
    Bouvier, A.
    Brandt, T. J.
    Bregeon, J.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Burgess, J. Michael
    Buson, S.
    Byrne, D.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Cecchi, C.
    Charles, E.
    Chaves, R. C. G.
    Chekhtman, A.
    Chiang, J.
    Chiaro, G.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Connaughton, V.
    Conrad, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Cutini, S.
    D'Ammando, F.
    de Angelis, A.
    de Palma, F.
    Dermer, C. D.
    Desiante, R.
    Digel, S. W.
    Dingus, B. L.
    Di Venere, L.
    Drell, P. S.
    Drlica-Wagner, A.
    Dubois, R.
    Favuzzi, C.
    Ferrara, E. C.
    Fitzpatrick, G.
    Foley, S.
    Franckowiak, A.
    Fukazawa, Y.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Goldstein, A.
    Granot, J.
    Grenier, I. A.
    Grove, J. E.
    Gruber, D.
    Guiriec, S.
    Hadasch, D.
    Hanabata, Y.
    Hayashida, M.
    Horan, D.
    Hou, X.
    Hughes, R. E.
    Inoue, Y.
    Jackson, M. S.
    Jogler, T.
    Johannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Kataoka, J.
    Kawano, T.
    Kippen, R. M.
    Knoedlseder, J.
    Kocevski, D.
    Kouveliotou, C.
    Kuss, M.
    Lande, J.
    Larsson, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC). Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Latronico, L.
    Lee, S. -H
    Longo, F.
    Loparco, F.
    Lovellette, M. N.
    Lubrano, P.
    Massaro, F.
    Mayer, M.
    Mazziotta, M. N.
    McBreen, S.
    McEnery, J. E.
    McGlynn, S.
    Michelson, P. F.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Moretti, E.
    Morselli, A.
    Murgia, S.
    Nemmen, R.
    Nuss, E.
    Nymark, T.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orienti, M.
    Orlando, E.
    Paciesas, W. S.
    Paneque, D.
    Panetta, J. H.
    Pelassa, V.
    Perkins, J. S.
    Pesce-Rollins, M.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Preece, R.
    Racusin, J. L.
    Raino, S.
    Rando, R.
    Rau, A.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Romoli, C.
    Roth, M.
    Ryde, F.
    Parkinson, P. M. Saz
    Schalk, T. L.
    Sgro, C.
    Siskind, E. J.
    Sonbas, E.
    Spandre, G.
    Spinelli, P.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takeuchi, Y.
    Tanaka, Y.
    Thayer, J. G.
    Thayer, J. B.
    Thompson, D. J.
    Tibaldo, L.
    Tierney, D.
    Tinivella, M.
    Torres, D. F.
    Tosti, G.
    Troja, E.
    Tronconi, V.
    Usher, T. L.
    Vandenbroucke, J.
    van der Horst, A. J.
    Vasileiou, V.
    Vianello, G.
    Vitale, V.
    von Kienlin, A.
    Winer, B. L.
    Wood, K. S.
    Wood, M.
    Xiong, S.
    Yang, Zhaoyu
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    THE FIRST FERMI-LAT GAMMA-RAY BURST CATALOG2013Ingår i: Astrophysical Journal Supplement Series, ISSN 0067-0049, E-ISSN 1538-4365, Vol. 209, nr 1Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (greater than or similar to 20 MeV) gamma-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above similar to 20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model.

  • 25. Aharonian, Felix
    et al.
    Akamatsu, Hiroki
    Akimoto, Fumie
    Allen, Steven W.
    Angelini, Lorella
    Audard, Marc
    Awaki, Hisamitsu
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Bamba, Aya
    Bautz, Marshall W.
    Blandford, Roger
    Brenneman, Laura W.
    Brown, Gregory
    Bulbul, Esra
    Cackett, Edward M.
    Canning, Rebecca E. A.
    Chernyakova, Maria
    Chiao, Meng P.
    Coppi, Paolo S.
    Costantini, Elisa
    de Plaa, Jelle
    de Vries, Cor P.
    den Herder, Jan-Willem
    Done, Chris
    Dotani, Tadayasu
    Ebisawa, Ken
    Eckart, Megan E.
    Enoto, Teruaki
    Ezoe, Yuichiro
    Fabian, Andrew C.
    Ferrigno, Carlo
    Foster, Adam R.
    Fujimoto, Ryuichi
    Fukazawa, Yasushi
    Furuzawa, Akihiro
    Galeazzi, Massimiliano
    Gallo, Luigi C.
    Gandhi, Poshak
    Giustini, Margherita
    Goldwurm, Andrea
    Gu, Liyi
    Guainazzi, Matteo
    Haba, Yoshito
    Hagino, Kouichi
    Hamaguchi, Kenji
    Harrus, Ilana M.
    Hatsukade, Isamu
    Hayashi, Katsuhiro
    Hayashi, Takayuki
    Hayashi, Tasuku
    Hayashida, Kiyoshi
    Hiraga, Junko S.
    Hornschemeier, Ann
    Hoshino, Akio
    Hughes, John P.
    Ichinohe, Yuto
    Iizuka, Ryo
    Inoue, Hajime
    Inoue, Shota
    Inoue, Yoshiyuki
    Ishida, Manabu
    Ishikawa, Kumi
    Ishisaki, Yoshitaka
    Iwai, Masachika
    Kaastra, Jelle
    Kallman, Tim
    Kamae, Tsuneyoshi
    Kataoka, Jun
    Katsuda, Satoru
    Kawai, Nobuyuki
    Kelley, Richard L.
    Kilbourne, Caroline A.
    Kitaguchi, Takao
    Kitamoto, Shunji
    Kitayama, Tetsu
    Kohmura, Takayoshi
    Kokubun, Motohide
    Koyama, Katsuji
    Koyama, Shu
    Kretschmar, Peter
    Krimm, Hans A.
    Kubota, Aya
    Kunieda, Hideyo
    Laurent, Philippe
    Lee, Shiu-Hang
    Leutenegger, Maurice A.
    Limousin, Olivier
    Loewenstein, Michael
    Long, Knox S.
    Lumr, David
    Madejski, Greg
    Maeda, Yoshitomo
    Maier, Daniel
    Makishima, Kazuo
    Markevitch, Maxim
    Matsumoto, Hironori
    Matsushita, Kyoko
    McCammon, Dan
    McNamara, Brian R.
    Mehdipour, Missagh
    Miller, Eric D.
    Miller, Jon M.
    Mineshige, Shin
    Mitsuda, Kazuhisa
    Mitsuishi, Ikuyuki
    Miyazawa, Takuya
    Mizuno, Tsunefumi
    Mori, Hideyuki
    Mori, Koji
    Mukai, Koji
    Murakami, Hiroshi
    Mushotzky, Richard F.
    Nakagawa, Takao
    Nakajima, Hiroshi
    Nakamori, Takeshi
    Nakashima, Shinya
    Nakazawa, Kazuhiro
    Norukawa, Kumiko K.
    Nobukawa, Masayoshi
    Noda, Hirofumi
    Odaka, Hirokazu
    Ohashi, Takaya
    Ohno, Masanori
    Okajima, Takashi
    Ota, Naomi
    Ozaki, Masanobu
    Paerels, Frits
    Paltani, Stephane
    Petre, Robert
    Pinto, Ciro
    Porter, Frederick S.
    Pottschmidt, Katja
    Reynolds, Christopher S.
    Safi-Harb, Samar
    Saito, Shinya
    Sakai, Kazuhiro
    Sasaki, Toru
    Sato, Goro
    Sato, Kosuke
    Sato, Rie
    Sawada, Makoto
    Schartel, Norbert
    Serlemitsos, Peter J.
    Seta, Hiromi
    Shidatsu, Megumi
    Simionescu, Aurora
    Smith, Randall K.
    Soong, Yang
    Stawarz, Lukasz
    Sugawara, Yasuharu
    Sugita, Satoshi
    Szymkowiak, Andrew
    Tajima, Hiroyasu
    Takahashi, Hiromitsu
    Takahashi, Tadayuki
    Takeda, Shin'ichiro
    Takei, Yoh
    Tamagawa, Toru
    Tamura, Takayuki
    Tanaka, Keigo
    Tanaka, Takaaki
    Tanaka, Yasuo
    Tanaka, Yasuyuki T.
    Tashiro, Makoto S.
    Tawara, Yuzuru
    Terada, Yukikatsu
    Terashima, Yuichi
    Tombesi, Francesco
    Tomida, Hiroshi
    Tsuboi, Yohko
    Tsujimoto, Masahiro
    Tsunemi, Hiroshi
    Tsuru, Takeshi Go
    Uchida, Hiroyuki
    Uchiyama, Hideki
    Uchiyama, Yasunobu
    Ueda, Shutaro
    Ueda, Yoshihiro
    Uno, Shin'ichiro
    Urry, C. Megan
    Ursino, Eugenio
    Wang, Qian H. S.
    Watanabe, Shin
    Werner, Norbert
    Wilkins, Dan R.
    Williams, Brian J.
    Yamada, Shinya
    Yamaguchi, Hiroya
    Yamaoka, Kazutaka
    Yamasaki, Noriko Y.
    Yamauchi, Makoto
    Yamauchi, Shigeo
    Yaqoob, Tahir
    Yatsu, Yoichi
    Yonetoku, Daisuke
    Zhuravleva, Irina
    Zoghbi, Abderahmen
    Atmospheric gas dynamics in the Perseus cluster observed with Hitomi2018Ingår i: Publications of the Astronomical Society of Japan, ISSN 0004-6264, E-ISSN 2053-051X, Vol. 70, nr 2, artikel-id 9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Extending the earlier measurements reported in Hitomi collaboration (2016, Nature, 535, 117), we examine the atmospheric gas motions within the central 100 kpc of the Perseus cluster using observations obtained with the Hitomi satellite. After correcting for the point spread function of the telescope and using optically thin emission lines, we find that the line-of-sight velocity dispersion of the hot gas is remarkably low and mostly uniform. The velocity dispersion reaches a maxima of approximately 200 km s(-1) toward the central active galactic nucleus (AGN) and toward the AGN inflated northwestern ghost bubble. Elsewhere within the observed region, the velocity dispersion appears constant around 100 km s(-1). We also detect a velocity gradient with a 100 km s(-1) amplitude across the cluster core, consistent with large-scale sloshing of the core gas. If the observed gas motions are isotropic, the kinetic pressure support is less than 10% of the thermal pressure support in the cluster core. The well-resolved, optically thin emission lines have Gaussian shapes, indicating that the turbulent driving scale is likely below 100 kpc, which is consistent with the size of the AGN jet inflated bubbles. We also report the first measurement of the ion temperature in the intracluster medium, which we find to be consistent with the electron temperature. In addition, we present a new measurement of the redshift of the brightest cluster galaxy NGC 1275.

  • 26. Aharonian, Felix
    et al.
    Akamatsu, Hiroki
    Akimoto, Fumie
    Allen, Steven W.
    Angelini, Lorella
    Audard, Marc
    Awaki, Hisamitsu
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Bamba, Aya
    Bautz, Marshall W.
    Blandford, Roger
    Brenneman, Laura W.
    Brown, Gregory
    Bulbul, Esra
    Cackett, Edward M.
    Chernyakova, Maria
    Chiao, Meng P.
    Coppi, Paolo S.
    Costantini, Elisa
    de Plaa, Jelle
    de Vries, Cor P.
    den Herder, Jan-Willem
    Done, Chris
    Dotani, Tadayasu
    Ebisawa, Ken
    Eckart, Megan E.
    Enoto, Teruaki
    Ezoe, Yuichiro
    Fabian, Andrew C.
    Ferrigno, Carlo
    Foster, Adam R.
    Fujimoto, Ryuichi
    Fukazawa, Yasushi
    Furukawa, Maki
    Furuzawa, Akihiro
    Galeazzi, Massimiliano
    Gallo, Luigi C.
    Gandhi, Poshak
    Giustini, Margherita
    Goldwurm, Andrea
    Gu, Liyi
    Guainazzi, Matteo
    Haba, Yoshito
    Hagino, Kouichi
    Hamaguchi, Kenji
    Harrus, Ilana M.
    Hatsukade, Isamu
    Hayashi, Katsuhiro
    Hayashi, Takayuki
    Hayashida, Kiyoshi
    Hiraga, Junko S.
    Hornschemeier, Ann
    Hoshino, Akio
    Hughes, John P.
    Ichinohe, Yuto
    Iizuka, Ryo
    Inoue, Hajime
    Inoue, Yoshiyuki
    Ishida, Manabu
    Ishikawa, Kumi
    Ishisaki, Yoshitaka
    Iwai, Masachika
    Kaastra, Jelle
    Kallman, Tim
    Kamae, Tsuneyoshi
    Kataoka, Jun
    Kato, Yuichi
    Katsuda, Satoru
    Kawai, Nobuyuki
    Kelley, Richard L.
    Kilbourne, Caroline A.
    Kitaguchi, Takao
    Kitamoto, Shunji
    Kitayama, Tetsu
    Kohmura, Takayoshi
    Kokubun, Motohide
    Koyama, Katsuji
    Koyama, Shu
    Kretschmar, Peter
    Krimm, Hans A.
    Kubota, Aya
    Kunieda, Hideyo
    Laurent, Philippe
    Lee, Shiu-Hang
    Leutenegger, Maurice A.
    Limousin, Olivier
    Loewenstein, Michael
    Long, Knox S.
    Lumb, David
    Madejski, Greg
    Maeda, Yoshitomo
    Maier, Daniel
    Makishima, Kazuo
    Markevitch, Maxim
    Matsumoto, Hironori
    Matsushita, Kyoko
    McCammon, Dan
    McNamara, Brian R.
    Mehdipour, Missagh
    Miller, Eric D.
    Miller, Jon M.
    Mineshige, Shin
    Mitsuda, Kazuhisa
    Mitsuishi, Ikuyuki
    Miyazawa, Takuya
    Mizuno, Tsunefumi
    Mori, Hideyuki
    Mori, Koji
    Mukai, Koji
    Murakami, Hiroshi
    Mushotzky, Richard F.
    Nakagawa, Takao
    Nakajima, Hiroshi
    Nakamori, Takeshi
    Nakashima, Shinya
    Nakazawa, Kazuhiro
    Norukawa, Kumiko K.
    Nobukawa, Masayoshi
    Noda, Hirofumi
    Odaka, Hirokazu
    Ohashi, Takaya
    Ohno, Masanori
    Okajima, Takashi
    Ota, Naomi
    Ozaki, Masanobu
    Paerels, Frits
    Paltani, Stephane
    Petre, Robert
    Pinto, Ciro
    Porter, Frederick S.
    Pottschmidt, Katja
    Reynolds, Christopher S.
    Safi-Harb, Samar
    Saito, Shinya
    Sakai, Kazuhiro
    Sasaki, Toru
    Sato, Goro
    Sato, Kosuke
    Sato, Rie
    Sawada, Makoto
    Schartel, Norbert
    Serlemitsos, Peter J.
    Seta, Hiromi
    Shidatsu, Megumi
    Simionescu, Aurora
    Smith, Randall K.
    Soong, Yang
    Stawarz, Lukasz
    Sugawara, Yasuharu
    Sugita, Satoshi
    Szymkowiak, Andrew
    Tajima, Hiroyasu
    Takahashi, Hiromitsu
    Takahashi, Tadayuki
    Takeda, Shinichiro
    Takei, Yoh
    Tamagawa, Toru
    Tamura, Takayuki
    Tanaka, Takaaki
    Tanaka, Yasuo
    Tanaka, Yasuyuki T.
    Tashiro, Makoto S.
    Tawara, Yuzuru
    Terada, Yukikatsu
    Terashima, Yuichi
    Tombesi, Francesco
    Tomida, Hiroshi
    Tsuboi, Yohko
    Tsujimoto, Masahiro
    Tsunemi, Hiroshi
    Tsuru, Takeshi Go
    Uchida, Hiroyuki
    Uchiyama, Hideki
    Uchiyama, Yasunobu
    Ueda, Shutaro
    Ueda, Yoshihiro
    Uno, Shinichiro
    Urry, C. Megan
    Ursino, Eugenio
    Watanabe, Shin
    Werner, Norbert
    Wilkins, Dan R.
    Williams, Brian J.
    Yamada, Shinya
    Yamaguchi, Hiroya
    Yamaoka, Kazutaka
    Yamasaki, Noriko Y.
    Yamauchi, Makoto
    Yamauchi, Shigeo
    Yaqoob, Tahir
    Yatsu, Yoichi
    Yonetoku, Daisuke
    Zhuravleva, Irina
    Zoghbi, Abderahmen
    Temperature structure in the Perseus cluster core observed with Hitomi2018Ingår i: Publications of the Astronomical Society of Japan, ISSN 0004-6264, E-ISSN 2053-051X, Vol. 70, nr 2, artikel-id 11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present paper explains the temperature structure of X-ray emitting plasma in the core of the Perseus cluster based on 1.8-20.0 keV data obtained with the Soft X-ray Spectrometer (SXS) on board the Hitomi Observatory. A series of four observations was carried out, with a total effective exposure time of 338 ks that covered a central region of similar to 7' in diameter. SXS was operated with an energy resolution of similar to 5 eV (full width at half maximum) at 5.9 keV. Not only fine structures of K-shell lines in He-like ions, but also transitions from higher principal quantum numbers were clearly resolved from Si through Fe. That enabled us to perform temperature diagnostics using the line ratios of Si, S, Ar, Ca, and Fe, and to provide the first direct measurement of the excitation temperature and ionization temperature in the Perseus cluster. The observed spectrum is roughly reproduced by a single-temperature thermal plasma model in collisional ionization equilibrium, but detailed line-ratio diagnostics reveal slight deviations from this approximation. In particular, the data exhibit an apparent trend of increasing ionization temperature with the atomic mass, as well as small differences between the ionization and excitation temperatures for Fe, the only element for which both temperatures could be measured. The best-fit two-temperature models suggest a combination of 3 and 5 keV gas, which is consistent with the idea that the observed small deviations from a single-temperature approximation are due to the effects of projecting the known radial temperature gradient in the cluster core along the line of sight. A comparison with the Chandra/ACIS and the XMM-Newton/RGS results, on the other hand, suggests that additional lower-temperature components are present in the intracluster medium (ICM), but not detectable with Hitomi/SXS giving its 1.8-20 keV energy band.

  • 27. Aharonian, Felix
    et al.
    Akamatsu, Hiroki
    Akimoto, Fumie
    Allen, Steven W.
    Angelini, Lorella
    Audard, Marc
    Awaki, Hisamitsu
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Bamba, Aya
    Bautz, Marshall W.
    Blandford, Roger
    Brenneman, Laura W.
    Brown, Gregory
    Bulbul, Esra
    Cackett, Edward M.
    Chernyakova, Maria
    Chiao, Meng P.
    Coppi, Paolo S.
    Costantini, Elisa
    de Plaa, Jelle
    de Vries, Cor P.
    den Herder, Jan-Willem
    Done, Chris
    Dotani, Tadayasu
    Ebisawa, Ken
    Eckart, Megan E.
    Enoto, Teruaki
    Ezoe, Yuichiro
    Fabian, Andrew C.
    Ferrigno, Carlo
    Foster, Adam R.
    Fujimoto, Ryuichi
    Fukazawa, Yasushi
    Furukawa, Maki
    Furuzawa, Akihiro
    Galeazzi, Massimiliano
    Gallo, Luigi C.
    Gandhi, Poshak
    Giustini, Margherita
    Goldwurm, Andrea
    Gu, Liyi
    Guainazzi, Matteo
    Haba, Yoshito
    Hagino, Kouichi
    Hamaguchi, Kenji
    Harrus, Ilana M.
    Hatsukade, Isamu
    Hayashi, Katsuhiro
    Hayashi, Takayuki
    Hayashida, Kiyoshi
    Hiraga, Junko S.
    Hornschemeier, Ann
    Hoshino, Akio
    Hughes, John P.
    Ichinohe, Yuto
    Iizuka, Ryo
    Inoue, Hajime
    Inoue, Yoshiyuki
    Ishida, Manabu
    Ishikawa, Kumi
    Ishisaki, Yoshitaka
    Iwai, Masachika
    Kaastra, Jelle
    Kallman, Tim
    Kamae, Tsuneyoshi
    Kataoka, Jun
    Katsuda, Satoru
    Kawai, Nobuyuki
    Kelley, Richard L.
    Kilbourne, Caroline A.
    Kitaguchi, Takao
    Kitamoto, Shunji
    Kitayama, Tetsu
    Kohmura, Takayoshi
    Kokubun, Motohide
    Koyama, Katsuji
    Koyama, Shu
    Kretschmar, Peter
    Krimm, Hans A.
    Kubota, Aya
    Kunieda, Hideyo
    Laurent, Philippe
    Lee, Shiu-Hang
    Leutenegger, Maurice A.
    Limousin, Olivier O.
    Loewenstein, Michael
    Long, Knox S.
    Lumb, David
    Madejski, Greg
    Maeda, Yoshitomo
    Maier, Daniel
    Makishima, Kazuo
    Markevitch, Maxim
    Matsumoto, Hironori
    Matsushita, Kyoko
    McCammon, Dan
    McNamara, Brian R.
    Mehdipour, Missagh
    Miller, Eric D.
    Miller, Jon M.
    Mineshige, Shin
    Mitsuda, Kazuhisa
    Mitsuishi, Ikuyuki
    Miyazawa, Takuya
    Mizuno, Tsunefumi
    Mori, Hideyuki
    Mori, Koji
    Mukai, Koji
    Murakami, Hiroshi
    Mushotzky, Richard F.
    Nakagawa, Takao
    Nakajima, Hiroshi
    Nakamori, Takeshi
    Nakashima, Shinya
    Nakazawa, Kazuhiro
    Norukawa, Kumiko K.
    Nobukawa, Masayoshi
    Noda, Hirofumi
    Odaka, Hirokazu
    Ogorzalek, Anna
    Ohashi, Takaya
    Ohno, Masanori
    Okajima, Takashi
    Ota, Naomi
    Ozaki, Masanobu
    Paerels, Frits
    Paltani, Stephane
    Petre, Robert
    Pinto, Ciro
    Porter, Frederick S.
    Pottschmidt, Katja
    Reynolds, Christopher S.
    Safi-Harb, Samar
    Saito, Shinya
    Sakai, Kazuhiro
    Sasaki, Toru
    Sato, Goro
    Sato, Kosuke
    Sato, Rie
    Sawada, Makoto
    Schartel, Norbert
    Serlemitsos, Peter J.
    Seta, Hiromi
    Shidatsu, Megumi
    Simionescu, Aurora
    Smith, Randall K.
    Soong, Yang
    Stawarz, Lukasz
    Sugawara, Yasuharu
    Sugita, Satoshi
    Szymkowiak, Andrew
    Tajima, Hiroyasu
    Takahashi, Hiromitsu
    Takahashi, Tadayuki
    Takeda, Shinichiro
    Takei, Yoh
    Tamagawa, Toru
    Tamura, Takayuki
    Tanaka, Takaaki
    Tanaka, Yasuo
    Tanaka, Yasuyuki T.
    Tashiro, Makoto S.
    Tawara, Yuzuru
    Terada, Yukikatsu
    Terashima, Yuichi
    Tombesi, Francesco
    Tomida, Hiroshi
    Tsuboi, Yohko
    Tsujimoto, Masahiro
    Tsunemi, Hiroshi
    Tsuru, Takeshi Go
    Uchida, Hiroyuki
    Uchiyama, Hideki
    Uchiyama, Yasunobu
    Ueda, Shutaro
    Ueda, Yoshihiro
    Uno, Shinichiro
    Urry, C. Megan
    Ursino, Eugenio
    Watanabe, Shin
    Werner, Norbert
    Wilkins, Dan R.
    Williams, Brian J.
    Yamada, Shinya
    Yamaguchi, Hiroya
    Yamaoka, Kazutaka
    Yamasaki, Noriko Y.
    Yamauchi, Makoto
    Yamauchi, Shigeo
    Yaqoob, Tahir
    Yatsu, Yoichi
    Yonetoku, Daisuke
    Zhuravleva, Irina
    Zoghbi, Abderahmen
    Measurements of resonant scattering in the Perseus Cluster core with Hitomi SXS2018Ingår i: Publications of the Astronomical Society of Japan, ISSN 0004-6264, E-ISSN 2053-051X, Vol. 70, nr 2, artikel-id 10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thanks to its high spectral resolution (similar to 5 eV at 6 keV), the Soft X-ray Spectrometer (SXS) on board Hitomi enables us to measure the detailed structure of spatially resolved emission lines from highly ionized ions in galaxy clusters for the first time. In this series of papers, using the SXS we have measured the velocities of gas motions, metallicities and the multi-temperature structure of the gas in the core of the Perseus Cluster. Here, we show that when inferring physical properties from line emissivities in systems like Perseus, the resonant scattering effect should be taken into account. In the Hitomi waveband, resonant scattering mostly affects the Fe XXV He alpha line (w)-the strongest line in the spectrum. The flux measured by Hitomi in this line is suppressed by a factor of similar to 1.3 in the inner similar to 30 kpc, compared to predictions for an optically thin plasma; the suppression decreases with the distance from the center. The w line also appears slightly broader than other lines from the same ion. The observed distortions of the w line flux, shape, and distance dependence are all consistent with the expected effect of the resonant scattering in the Perseus core. By measuring the ratio of fluxes in optically thick (w) and thin (Fe XXV forbidden, He beta, Ly alpha) lines, and comparing these ratios with predictions from Monte Carlo radiative transfer simulations, the velocities of gas motions have been obtained. The results are consistent with the direct measurements of gas velocities from line broadening described elsewhere in this series, although the systematic and statistical uncertainties remain significant. Further improvements in the predictions of line emissivities in plasma models, and deeper observations with future X-ray missions offering similar or better capabilities to the Hitomi SXS, will enable resonant scattering measurements to provide powerful constraints on the amplitude and anisotropy of cluster gas motions.

  • 28. Aharonian, Felix
    et al.
    Akamatsu, Hiroki
    Akimoto, Fumie
    Allen, Steven W.
    Angelini, Lorella
    Audard, Marc
    Awaki, Hisamitsu
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Bamba, Aya
    Bautz, Marshall W.
    Blandford, Roger
    Brenneman, Laura W.
    Brown, Gregory
    Bulbul, Esra
    Cackett, Edward M.
    Chernyakova, Maria
    Chiao, Meng P.
    Coppi, Paolo S.
    Costantini, Elisa
    de Plaa, Jelle
    de Vries, Cor P.
    den Herder, Jan-Willem
    Done, Chris
    Dotani, Tadayasu
    Ebisawa, Ken
    Eckart, Megan E.
    Enoto, Teruaki
    Ezoe, Yuichiro
    Fabian, Andrew C.
    Ferrigno, Carlo
    Foster, Adam R.
    Fujimoto, Ryuichi
    Fukazawa, Yasushi
    Furuzawa, Akihiro
    Galeazzi, Massimiliano
    Gallo, Luigi C.
    Gandhi, Poshak
    Giustini, Margherita
    Goldwurm, Andrea
    Gu, Liyi
    Guainazzi, Matteo
    Haba, Yoshito
    Hagino, Kouichi
    Hamaguch, Kenji
    Harrus, Ilana M.
    Hatsukade, Isamu
    Hayashi, Katsuhiro
    Hayashi, Takayuki
    Hayashida, Kiyoshi
    Hiraga, Junko S.
    Hornschemeier, Ann
    Hoshino, Akio
    Hughes, John P.
    Ichinohe, Yuto
    Iizuka, Ryo
    Inoue, Hajime
    Inoue, Yoshiyuki
    Ishida, Manabu
    Ishikawa, Kumi
    Ishisaki, Yoshitaka
    Kaastra, Jelle
    Kallman, Tim
    Kamae, Tsuneyoshi
    Kataoka, Jun
    Katsuda, Satoru
    Kawai, Nobuyuki
    Kelley, Richard L.
    Kilbourne, Caroline A.
    Kitaguchi, Takao
    Kitamoto, Shunji
    Kitayama, Tetsu
    Kohmura, Takayoshi
    Kokubun, Motohide
    Koyama, Katsuji
    Koyama, Shu
    Kretschmar, Peter
    Krimm, Hans A.
    Kubota, Aya
    Kunieda, Hideyo
    Laurent, Philippe
    Lee, Shiu-Hang
    Leutenegger, Maurice A.
    Limousin, Olivier
    Loewenstein, Michael
    Long, Knox S.
    Lumb, David
    Madejski, Greg
    Maeda, Yoshitomo
    Maier, Daniel
    Makishima, Kazuo
    Markevitch, Maxim
    Matsumoto, Hironori
    Matsushita, Kyoko
    McCammon, Dan
    McNamara, Brian R.
    Mehdipour, Missagh
    Miller, Eric D.
    Miller, Jon M.
    Mineshige, Shin
    Mitsuda, Kazuhisa
    Mitsuishi, Ikuyuki
    Miyazawa, Takuya
    Mizuno, Tsunefumi
    Mori, Hideyuki
    Mori, Koji
    Mukai, Koji
    Murakami, Hiroshi
    Mushotzky, Richard F.
    Nakagawa, Takao
    Nakajima, Hiroshi
    Nakamori, Takeshi
    Nakashima, Shinya
    Nakazawa, Kazuhiro
    Nobukawa, Kumiko K.
    Nobukawa, Masayoshi
    Noda, Hirofumi
    Odaka, Hirokazu
    Ohashi, Takaya
    Ohno, Masanori
    Okajima, Takashi
    Ota, Naomi
    Ozaki, Masanobu
    Paerels, Frits
    Paltani, Stephane
    Petre, Robert
    Pinto, Ciro
    Porter, Frederick S.
    Pottschmidt, Katja
    Reynolds, Christopher S.
    Safi-Harb, Samar
    Saito, Shinya
    Sakai, Kazuhiro
    Sasaki, Toru
    Sato, Goro
    Sato, Kosuke
    Sato, Rie
    Sato, Toshiki
    Sawada, Makoto
    Schartel, Norbert
    Serlemtsos, Peter J.
    Seta, Hiromi
    Shidatsu, Megumi
    Simionescu, Aurora
    Smith, Randall K.
    Soong, Yang
    Stawarz, Lukasz
    Sugawara, Yasuharu
    Sugita, Satoshi
    Szymkowiak, Andrew
    Tajima, Hiroyasu
    Takahashi, Hiromitsu
    Takahashi, Tadayuki
    Takeda, Shin'ichiro
    Takei, Yoh
    Tamagawa, Toru
    Tamura, Takayuki
    Tanaka, Takaaki
    Tanaka, Yasuo
    Tanaka, Yasuyuki T.
    Tashiro, Makoto S.
    Tawara, Yuzuru
    Terada, Yukikatsu
    Terashima, Yuichi
    Tombesi, Francesco
    Tomida, Hiroshi
    Tsuboi, Yohko
    Tsujimoto, Masahiro
    Tsunemi, Hiroshi
    Tsuru, Takeshi Go
    Uchida, Hiroyuki
    Uchiyama, Hideki
    Uchiyama, Yasunobu
    Ueda, Shutaro
    Ueda, Yoshihiro
    Uno, Shin'ichiro
    Urry, C. Megan
    Ursino, Eugenio
    Watanabe, Shin
    Werner, Norbert
    Wilkins, Dan R.
    Williams, Brian J.
    Yamada, Shinya
    Yamaguchi, Hiroya
    Yamaoka, Kazutaka
    Yamasaki, Noriko Y.
    Yamauchi, Makoto
    Yamauchi, Shigeo
    Yaqoob, Tahir
    Yatsu, Yoichi
    Yonetoku, Daisuke
    Zhuravleva, Irina
    Zoghbi, Abderahmen
    Tominaga, Nozomu
    Moriya, Takashi J.
    Search for thermal X-ray features from the Crab nebula with the Hitomi soft X-ray spectrometer2018Ingår i: Publications of the Astronomical Society of Japan, ISSN 0004-6264, E-ISSN 2053-051X, Vol. 70, nr 2, artikel-id 14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Crab nebula originated from a core-collapse supernova (SN) explosion observed in 1054 AD. When viewed as a supernova remnant (SNR), it has an anomalously low observed ejecta mass and kinetic energy for an Fe-core-collapse SN. Intensive searches have been made for a massive shell that solves this discrepancy, but none has been detected. An alternative idea is that SN 1054 is an electron-capture (EC) explosion with a lower explosion energy by an order of magnitude than Fe-core-collapse SNe. X-ray imaging searches were performed for the plasma emission from the shell in the Crab outskirts to set a stringent upper limit on the X-ray emitting mass. However, the extreme brightness of the source hampers access to its vicinity. We thus employed spectroscopic technique using the X-ray micro-calorimeter on board the Hitomi satellite. By exploiting its superb energy resolution, we set an upper limit for emission or absorption features from as yet undetected thermal plasma in the 2-12 keV range. We also re-evaluated the existing Chandra and XMM-Newton data. By assembling these results, a new upper limit was obtained for the X-ray plasma mass of less than or similar to 1 M-circle dot for a wide range of assumed shell radius, size, and plasma temperature values both in and out of collisional equilibrium. To compare with the observation, we further performed hydrodynamic simulations of the Crab SNR for two SN models (Fe-core versus EC) under two SN environments (uniform interstellar medium versus progenitor wind). We found that the observed mass limit can be compatible with both SN models if the SN environment has a low density of less than or similar to 0.03 cm(-3) (Fe core) or less than or similar to 0.1 cm(-3) (EC) for the uniform density, or a progenitor wind density somewhat less than that provided by amass loss rate of 10(-5) M-circle dot yr(-1) at 20 km s(-1) for the wind environment.

  • 29. Aharonian, Felix
    et al.
    Akamatsu, Hiroki
    Akimoto, Fumie
    Allen, Steven W.
    Angelini, Lorella
    Audard, Marc
    Awaki, Hisamitsu
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Bamba, Aya
    Bautz, Marshall W.
    Blandford, Roger
    Brenneman, Laura W.
    Brown, Gregory
    Bulbul, Esra
    Cackett, Edward M.
    Chernyakova, Maria
    Chiao, Meng P.
    Coppi, Paolo S.
    Costantini, Elisa
    de Plaa, Jelle
    de Vries, Cor P.
    den Herder, Jan-Willem
    Done, Chris
    Dotani, Tadayasu
    Ebisawa, Ken
    Eckart, Megan E.
    Enoto, Teruaki
    Ezoe, Yuichiro
    Fabian, Andrew C.
    Ferrigno, Carlo
    Foster, Adam R.
    Fujimoto, Ryuichi
    Fukazawa, Yasushi
    Furuzawa, Akihiro
    Galeazzi, Massimiliano
    Gallo, Luigi C.
    Gandhi, Poshak
    Giustini, Margherita
    Goldwurm, Andrea
    Gu, Liyi
    Guainazzi, Matteo
    Haba, Yoshito
    Hagino, Kouichi
    Hamaguchi, Kenji
    Harrus, Ilana M.
    Hatsukade, Isamu
    Hayashi, Katsuhiro
    Hayashi, Takayuki
    Hayashida, Kiyoshi
    Hell, Natalie
    Hiraga, Junko S.
    Hornschemeier, Ann
    Hoshino, Akio
    Hughes, John P.
    Ichinohe, Yuto
    Iizuka, Ryo
    Inoue, Hajime
    Inoue, Yoshiyuki
    Ishida, Manabu
    Ishikawa, Kumi
    Ishisaki, Yoshitaka
    Iwai, Masachika
    Kaastra, Jelle
    Kallman, Tim
    Kamae, Tsuneyoshi
    Kataoka, Jun
    Katsuda, Satoru
    Kawai, Nobuyuki
    Kelley, Richard L.
    Kilbourne, Caroline A.
    Kitaguchi, Takao
    Kitamoto, Shunji
    Kitayama, Tetsu
    Kohmura, Takayoshi
    Kokubun, Motohide
    Koyama, Katsuji
    Koyama, Shu
    Kretschmar, Peter
    Krimm, Hans A.
    Kubota, Aya
    Kunieda, Hideyo
    Laurent, Philippe
    Lee, Shiu-Hang
    Leutenegger, Maurice A.
    Limousin, Olivier O.
    Loewenstein, Michael
    Long, Knox S.
    Lumb, David
    Madejski, Greg
    Maeda, Yoshitomo
    Maier, Daniel
    Makishima, Kazuo
    Markevitch, Maxim
    Matsumoto, Hironori
    Matsushita, Kyoko
    McCammon, Dan
    McNamara, Brian R.
    Mehdipour, Missagh
    Miller, Eric D.
    Miller, Jon M.
    Mineshige, Shin
    Mitsuda, Kazuhisa
    Mitsuishi, Ikuyuki
    Miyazawa, Takuya
    Mizuno, Tsunefumi
    Mori, Hideyuki
    Mori, Koji
    Mukai, Koji
    Murakami, Hiroshi
    Mushotzky, Richard F.
    Nakagawa, Takao
    Nakajima, Hiroshi
    Nakamori, Takeshi
    Nakashima, Shinya
    Nakazawa, Kazuhiro
    Norukawa, Kumiko K.
    Nobukawa, Masayoshi
    Noda, Hirofumi
    Odaka, Hirokazu
    Ohashi, Takaya
    Ohno, Masanori
    Okajima, Takashi
    Ota, Naomi
    Ozaki, Masanobu
    Paerels, Frits
    Paltani, Stephane
    Petre, Robert
    Pinto, Ciro
    Porter, Frederick S.
    Pottschmidt, Katja
    Reynolds, Christopher S.
    Safi-Harb, Samar
    Saito, Shinya
    Sakai, Kazuhiro
    Sasaki, Toru
    Sato, Goro
    Sato, Kosuke
    Sato, Rie
    Sawada, Makoto
    Schartel, Norbert
    Serlemitsos, Peter J.
    Seta, Hiromi
    Shidatsu, Megumi
    Simionescu, Aurora
    Smith, Randall K.
    Soong, Yang
    Stawarz, Lukasz
    Sugawara, Yasuharu
    Sugita, Satoshi
    Szymkowiak, Andrew
    Tajima, Hiroyasu
    Takahashi, Hiromitsu
    Takahashi, Tadayuki
    Takeda, Shin'ichiro
    Takei, Yoh
    Tamagawa, Toru
    Tamura, Takayuki
    Tanaka, Takaaki
    Tanaka, Yasuo
    Tanaka, Yasuyuki T.
    Tashiro, Makoto S.
    Tawara, Yuzuru
    Terada, Yukikatsu
    Terashima, Yuichi
    Tombesi, Francesco
    Tomida, Hiroshi
    Tsuboi, Yohko
    Tsujimoto, Masahiro
    Tsunemi, Hiroshi
    Tsuru, Takeshi Go
    Uchida, Hiroyuki
    Uchiyama, Hideki
    Uchiyama, Yasunobu
    Ueda, Shutaro
    Ueda, Yoshihiro
    Uno, Shin'ichiro
    Urry, C. Megan
    Ursino, Eugenio
    Watanabe, Shin
    Werner, Norbert
    Wilkins, Dan R.
    Williams, Brian J.
    Yamada, Shinya
    Yamaguchi, Hiroya
    Yamaoka, Kazutaka
    Yamasaki, Noriko Y.
    Yamauchi, Makoto
    Yamauchi, Shigeo
    Yaqoob, Tahir
    Yatsu, Yoichi
    Yonetoku, Daisuke
    Zhuravleva, Irina
    Zoghbi, Abderahmen
    Raassen, A. J. J.
    Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi2018Ingår i: Publications of the Astronomical Society of Japan, ISSN 0004-6264, E-ISSN 2053-051X, Vol. 70, nr 2, artikel-id 12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Hitomi Soft X-ray Spectrometer spectrum of the Perseus cluster, with similar to 5 eV resolution in the 2-9 keV band, offers an unprecedented benchmark of the atomic modeling and database for hot collisional plasmas. It reveals both successes and challenges of the current atomic data and models. The latest versions of AtomDB/APEC (3.0.8), SPEX (3.03.00), and CHIANTI (8.0) all provide reasonable fits to the broad-band spectrum, and are in close agreement on best-fit temperature, emission measure, and abundances of a few elements such as Ni. For the Fe abundance, the APEC and SPEX measurements differ by 16%, which is 17 times higher than the statistical uncertainty. This is mostly attributed to the differences in adopted collisional excitation and dielectronic recombination rates of the strongest emission lines. We further investigate and compare the sensitivity of the derived physical parameters to the astrophysical source modeling and instrumental effects. The Hitomi results show that accurate atomic data and models are as important as the astrophysical modeling and instrumental calibration aspects. Substantial updates of atomic databases and targeted laboratory measurements are needed to get the current data and models ready for the data from the next Hitomi-level mission.

  • 30. Aharonian, Felix
    et al.
    Akamatsu, Hiroki
    Akimoto, Fumie
    Allen, Steven W.
    Angelini, Lorella
    Audard, Marc
    Awaki, Hisamitsu
    Axelsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Bamba, Aya
    Bautz, Marshall W.
    Blandford, Roger
    Brenneman, Laura W.
    Brown, Gregory
    Bulbul, Esra
    Cackett, Edward M.
    Chernyakova, Maria
    Chiao, Meng P.
    Coppi, Paolo S.
    Costantini, Elisa
    de Plaa, Jelle
    de Vries, Cor P.
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    Hitomi X-ray observation of the pulsar wind nebula G21.5-0.92018Ingår i: Publications of the Astronomical Society of Japan, ISSN 0004-6264, E-ISSN 2053-051X, Vol. 70, nr 3, artikel-id 38Artikel i tidskrift (Refereegranskat)