Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived from First-Year Fermi Large Area Telescope Data
2010 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 104, no 101101Article in journal (Refereed) Published
We report on the ﬁrst Fermi Large Area Telescope (LAT) measurements of the so-called ‘‘extra- galactic’’ diffuse gamma-ray emission (EGB). This component of the diffuse Υ-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modeling of the bright foreground diffuse Galactic gamma-ray emission, the detected LAT sources, and the solar gamma-ray emission. We ﬁnd the spectrum of the EGB is consistent with a power law with a differential spectral index of 2.41 \pm 0.05 and intensity I(>100 MeV)=(1.03\pm 0.17) e-5 cm**2 s **-1 sr**-1 , where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data.
Place, publisher, year, edition, pages
2010. Vol. 104, no 101101
IdentifiersURN: urn:nbn:se:su:diva-38906DOI: 10.1103/PhysRevLett.104.101101ISI: 000275543500007OAI: oai:DiVA.org:su-38906DiVA: diva2:317449
Totalt 183 författare.2010-05-032010-05-032011-12-06Bibliographically approved