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Fermi-LAT observations of the Sagittarius B complex.
- Source :
-
Astronomy & Astrophysics / Astronomie et Astrophysique . Aug2015, Vol. 580, p1-7. 7p. - Publication Year :
- 2015
-
Abstract
- Aims. We use 5 years of Fermi-LAT data towards the Galactic-centre giant molecular cloud complex, Sagittarius B, to test questions of how well-mixed the Galactic component of cosmic rays are and what the level of the cosmic-ray sea in different parts of the Galaxy is. Methods. We use dust-opacity maps from the Planck satellite to obtain independent methods for background subtraction and an estimate for the mass of the region. We then present high-quality spectra of γ-ray emission from 0.3 to 30 GeV and obtain an estimate of the cosmic-ray spectrum from the region. Results. We obtain an estimate of the mass of the region of 1.5 ± 0.2 × 107 Mo using the Planck data, which agrees well with molecular-line-derived estimates for the same region. We find that the γ-ray flux from this region is fitted well with a cosmic-ray spectrum that is the same as is observed locally, with evidence of a small over-density at intermediate (1-10 GeV) energies. Conclusions. We conclude that the γ-ray and cosmic-ray spectrum in the region can be well-fitted using a local cosmic-ray spectrum. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00046361
- Volume :
- 580
- Database :
- Academic Search Index
- Journal :
- Astronomy & Astrophysics / Astronomie et Astrophysique
- Publication Type :
- Academic Journal
- Accession number :
- 109218629
- Full Text :
- https://doi.org/10.1051/0004-6361/201425233