Change search
Refine search result
1 - 9 of 9
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Adamo, Angela
    et al.
    Stockholm University, Faculty of Science, Department of Astronomy.
    Östlin, Göran
    Stockholm University, Faculty of Science, Department of Astronomy.
    Zackrisson, Erik
    Stockholm University, Faculty of Science, Department of Astronomy.
    Hayes, Matthew
    Observatoire Astronomique de l'Université de Genève.
    Cumming, Robert
    Stockholm University, Faculty of Science, Department of Astronomy.
    Micheva, Genoveva
    Stockholm University, Faculty of Science, Department of Astronomy.
    Super star clusters in Haro 11: properties of a very young starburst and evidence for a near-infrared flux excess2010In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, MNRAS, Vol. 407, no 2, p. 870-890Article in journal (Refereed)
    Abstract [en]

    We have used multiband imaging to investigate the nature of an extreme starburst environment in the nearby Lyman break galaxy analogue Haro 11 (ESO350-IG038) by means of its stellar cluster population. The central starburst region has been observed in eight different high-resolution Hubble Space Telescope (HST) wavebands, sampling the stellar and gas components from UV to near-infrared. Photometric imaging of the galaxy was also carried out at 2.16μm by NaCo AO instrument at the ESO Very Large Telescope. We constructed integrated spectral energy distributions (SEDs) for about 200 star clusters located in the active star-forming regions and compared them with single stellar population models (suitable for physical properties of very young cluster population) in order to derive ages, masses and extinctions of the star clusters. The cluster age distribution we recover confirms that the present starburst has lasted for 40Myr, and shows a peak of cluster formation only 3.5 Myr old. With such an extremely young cluster population, Haro 11 represents a unique opportunity to investigate the youngest phase of the cluster formation process and evolution in starburst systems. We looked for possible relations between cluster ages, extinctions and masses. Extinction tends to diminish as a function of the cluster age, but the spread is large and reaches the highest dispersion for clusters in partial embedded phases (<5Myr). A fraction of low-mass (below 104 Msolar), very young (1-3Myr) clusters is missing, either because they are embedded in the parental molecular cloud and heavily extinguished, or because of blending with neighbouring clusters. The range of the cluster masses is wide; we observe that more than 30 per cent of the clusters have masses above 105 Msolar, qualifying them as super star clusters. Almost half of the cluster sample is affected by flux excesses at wavelengths >8000Å which cannot be explained by simple stellar evolutionary models. Fitting SED models over all wavebands leads to systematic overestimates of cluster ages and incorrect masses for the stellar population supplying the light in these clusters. We show that the red excess affects also the HST F814W filter, which is typically used to constrain cluster physical properties. The clusters which show the red excess are younger than 40Myr we discuss possible physical explanations for the phenomenon. Finally, we estimate that Haro 11 has produced bound clusters at a rate almost a factor of 10 higher than the massive and regular spirals, like the Milky Way. The present cluster formation efficiency is ~38 per cent of the galactic star formation rate.

  • 2. Chugai, Nikolai N.
    et al.
    Blinnikov, Sergei I.
    Cumming, Robert J.
    Stockholm University, Faculty of Science, Department of Astronomy.
    Lundqvist, Peter
    Stockholm University, Faculty of Science, Department of Astronomy.
    Bragaglia, Angela
    Filippenko, Alexei V.
    Leonard, Douglas C.
    Matheson, Thomas
    Sollerman, Jesper
    Stockholm University, Faculty of Science, Department of Astronomy.
    The Type IIn supernova 1994W: evidence for the explosive ejection of a circumstellar envelope2004In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 352, p. 1213-1231Article in journal (Refereed)
    Abstract [en]

    We present and analyse spectra of the Type IIn supernova (SN) 1994W obtained between 18 and 203d after explosion. During the luminous phase (first 100d) the line profiles are composed of three major components: (i) narrow P-Cygni lines with the absorption minima at -700kms-1 (ii) broad emission lines with blue velocity at zero intensity ~4000km s-1 and (iii) broad, smooth wings extending out to at least ~5000kms-1, most apparent in Hα. These components are identified with an expanding circumstellar (CS) envelope, shocked cool gas in the forward post-shock region, and multiple Thomson scattering in the CS envelope, respectively. The absence of broad P-Cygni lines from the SN is the result of the formation of an optically thick, cool, dense shell at the interface of the ejecta and the CS envelope. Models of the SN deceleration and Thomson scattering wings are used to recover the density (n~ 109cm-3), radial extent [~(4-5) × 1015cm] and Thomson optical depth (τT>~ 2.5) of the CS envelope during the first month. The plateau-like SN light curve is reproduced by a hydrodynamical model and is found to be powered by a combination of internal energy leakage after the explosion of an extended pre-SN (~1015cm) and subsequent luminosity from CS interaction. The pre-explosion kinematics of the CS envelope is recovered, and is close to homologous expansion with outer velocity ~1100kms-1 and a kinematic age of ~1.5yr. The high mass (~0.4Msolar) and kinetic energy (~2 × 1048erg) of the CS envelope, combined with low age, strongly suggest that the CS envelope was explosively ejected ~1.5yr prior to the SN explosion.

  • 3.
    Cumming, Robert James
    Stockholm University, Faculty of Science, Department of Astronomy. Stockholm University, Faculty of Science, Department of Astronomy.
    En solskenshistoria2008In: Populär Astronomi, ISSN 1650-7177, Vol. 9, no 3Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Martin Asplund, nytillträdd forskningschef på Max-Planck-Institutet för astrofysik i Munchen, är numera en av Tysklands mäktigaste astronomer. Vi träffade honom på hemmaplan i Uppsala för att prata om solen, stjärnorna och livet.

  • 4.
    Cumming, Robert James
    Stockholm University, Faculty of Science, Department of Astronomy.
    Kroppen i rymden2008In: Populär Astronomi, ISSN 1650-7177, Vol. 9, no 4Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Dag Linnarsson, professor i fysiologi och expert på rymdmedicin, intervjuas.

  • 5.
    Cumming, Robert James
    Stockholm University, Faculty of Science, Department of Astronomy.
    Mot planeterna!2008In: Populär Astronomi, ISSN 1650-7177, Vol. 9, no 1Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Intervju med Stas Barabash, professor i rymdfysik.

  • 6.
    Cumming, Robert James
    Stockholm University, Faculty of Science, Department of Astronomy.
    Politik och partiklar2008In: Populär Astronomi, ISSN 1650-7177, Vol. 9, no 2Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Från kommunismens Polen till dagens Skandinavien, från 1980-talets CERN till dagens LHC. Anna Lipniacka söker avslöja universums hemligheter med hjälp av dess minsta beståndsdelar. Men politiken har en tendens att komma i vägen ibland.

  • 7.
    Cumming, Robert James
    Stockholm University, Faculty of Science, Department of Astronomy.
    Sökes: framtidens astronauter2008In: Populär Astronomi, ISSN 1650-7177, Vol. 9, no 2Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Den europeiska astronautkåren behöver förnyelse. Därför sätter rymdorganet ESA igång med att välja ut fyra nya astronauter. Processen är lång och krävande, men de som lyckas kan bli de första europeerna på månen eller Mars.

  • 8.
    Cumming, Robert James
    et al.
    Stockholm University, Faculty of Science, Department of Astronomy.
    Fathi, Kambiz
    Stockholm University, Faculty of Science, Department of Astronomy.
    Östlin, Göran
    Stockholm University, Faculty of Science, Department of Astronomy.
    Marquart, Thomas
    Masegosa, Josefa
    Bergvall, Nils
    Amram, Philippe
    Stellar dynamics of blue compact galaxies.: II. Further indications of a merger in ESO 338-IG042008In: Astronomy & Astrophysics, Vol. 479, no 3Article in journal (Refereed)
    Abstract [en]

    Context: Luminous blue compact galaxies, common at z ~ 1 but now relatively rare, show disturbed kinematics in emission lines. Aims: As part of a programme to understand their formation and evolution, we have investigated the stellar dynamics of a number of nearby objects in this class. Methods: We obtained long-slit spectra with VLT/FORS2 in the spectral region covering the near-infrared calcium triplet. In this paper we focus on the well-known luminous blue compact galaxy ESO 338-IG04 (Tololo 1924-416). A previous investigation, using Fabry-Perot interferometry, showed that this galaxy has a chaotic Hα velocity field, indicating that either the galaxy is not in dynamical equilibrium or that Hα does not trace the gravitational potential due to feedback from star formation. Results: Along the apparent major axis, the stellar and ionised gas velocities for the most part follow each other. The chaotic velocity field must therefore be a sign that the young stellar population in ESO 338-IG04 is not in dynamical equilibrium. The most likely explanation, which is also supported by its morphology, is that the galaxy has experienced a merger and that this has triggered the current starburst. Summarising the results of our programme so far, we note that emission-line velocity fields are not always reliable tracers of stellar motions, and go on to assess the implications for kinematic studies of similar galaxies at intermediate redshift.

  • 9.
    Cumming, Robert
    et al.
    Stockholm University, Faculty of Science, Department of Astronomy.
    Östlin, Göran
    Stockholm University, Faculty of Science, Department of Astronomy.
    Marquart, Thomas
    Fathi, Kambiz
    Stockholm University, Faculty of Science, Department of Astronomy.
    Bergvall, Nils
    Adamo, Angela
    Stockholm University, Faculty of Science, Department of Astronomy.
    Stellar kinematics in blue compact galaxies2009Report (Other academic)
    Abstract [en]

    In a programme of observations of local luminous blue compact galaxies (BCGs), we are investigating kinematics by using tracers of both stars and ionized gas. Here we summarise our program and present new data on the local Lyman break galaxy analogue Haro 11. From spatially-resolved spectroscopy around the near-infrared Ca II triplet, we find that its stars and ionized gas have similar velocity fields. Our programme so far indicates however that emission line velocities can differ locally by a few tens of km/s from the Ca II values. Comparing our data to simple stellar population models, we assess which stellar population the Ca II triplet traces and its potential beyond the local universe.

1 - 9 of 9
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf