Fermi-LAT Study of Gamma-ray Emission in the Direction of Supernova Remnant W49B
Collaboration
•9 pages
Published in:
- Astrophys.J. 722 (2010) 1303-1311
e-Print:
- 1008.4190 [astro-ph.HE]
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Abstract: (arXiv)
We present an analysis of the gamma-ray data obtained with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the direction of SNR W49B (G43.3-0.2). A bright unresolved gamma-ray source detected at a significance of 38 sigma is found to coincide with SNR W49B. The energy spectrum in the 0.2-200 GeV range gradually steepens toward high energies. The luminosity is estimated to be 1.5x10^{36} (D/8 kpc)^2 erg s^-1 in this energy range. There is no indication that the gamma-ray emission comes from a pulsar. Assuming that the SNR shell is the site of gamma-ray production, the observed spectrum can be explained either by the decay of neutral pi mesons produced through the proton-proton collisions or by electron bremsstrahlung. The calculated energy density of relativistic particles responsible for the LAT flux is estimated to be remarkably large, U_{e,p}>10^4 eV cm^-3, for either gamma-ray production mechanism.Note:
- 9 pages, 10 figures
- acceleration of particles
- ISM: individual(W49B)
- radiation mechanisms: non-thermal
- gamma ray: energy spectrum: measured
- pi0: radiative decay
- energy: density
- electron: bremsstrahlung
- particle: relativistic
- GLAST
- supernova
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