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Title: The supernova remnant W49B as seen with H.E.S.S. and Fermi-LAT

The supernova remnant (SNR) W49B originated from a core-collapse supernova that occurred between one and four thousand years ago, and subsequently evolved into a mixed-morphology remnant, which is interacting with molecular clouds (MC). Gamma-ray observations of SNR-MC associations are a powerful tool to constrain the origin of Galactic cosmic rays, as they can probe the acceleration of hadrons through their interaction with the surrounding medium and subsequent emission of non-thermal photons. Here, we report the detection of a γ-ray source coincident with W49B at very high energies (VHE; E > 100 GeV) with the H.E.S.S. Cherenkov telescopes together with a study of the source with five years of Fermi-LAT high-energy γ-ray (0.06–300 GeV) data. The smoothly connected, combined source spectrum, measured from 60 MeV to multi-TeV energies, shows two significant spectral breaks at 304 ± 20 MeV and 8.4 -2.5 +2.2 GeV; the latter is constrained by the joint fit from the two instruments. The detected spectral features are similar to those observed in several other SNR-MC associations and are found to be indicative of γ-ray emission produced through neutral-pion decay.
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Publication Date:
Grant/Contract Number:
AC02-76SF00515; AST-9800334; AST-0098562; AST-0100793; AST-0228993; AST-0507657
Type:
Accepted Manuscript
Journal Name:
Astronomy and Astrophysics
Additional Journal Information:
Journal Volume: 612; Journal ID: ISSN 0004-6361
Publisher:
EDP Sciences
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE; National Science Foundation (NSF)
Contributing Orgs:
H.E.S.S. Collaboration; From Fermi-LAT Collaboration
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; gamma rays general; ISM: supernova remnants; ISM: clouds
OSTI Identifier:
1434923