Discovery of an extended source of gamma-ray emission in the Southern hemisphere
Abstract
We report the discovery of a ∼3.4°-wide region of high-energy emission in data from the Fermi LAT satellite. The centroid of the emission is located in the Southern hemisphere sky, a few degrees away from the plane of the Galaxy at the Galactic coordinates l = 350.6°, b = -4.7°. It shows a hard spectrum that is compatible with a simple power law, dN/dE∝ E^{-Γ }, in the energy range 0.7-500 GeV, with a spectral index Γ = 1.68 ± 0.04stat ± 0.1sys. The integrated source photon flux above 0.7 GeV is (4.71 ± 0.49stat ± 2.13sys) × 10-9 cm-2 s-1. We discuss several hypotheses for the nature of the source, particularly that the emission comes from the shell of an unknown supernova remnant.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 2018
- DOI:
- 10.1093/mnras/stx2779
- arXiv:
- arXiv:1609.06225
- Bibcode:
- 2018MNRAS.474..102A
- Keywords:
-
- cosmic rays;
- ISM: supernova remnants;
- gamma-rays: general;
- gamma-rays: ISM;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- MNRAS published online 2017 October