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Title: Attenuation of VHE Gamma Rays by the Milky Way Interstellar Radiation Field

Journal Article · · Astrophysical Journal
DOI:https://doi.org/10.1086/503524· OSTI ID:881539

The attenuation of very high energy gamma rays by pair production on the Galactic interstellar radiation field has long been thought of as negligible. However, a new calculation of the interstellar radiation field consistent with multi-wavelength observations by DIRBE and FIRAS indicates that the energy density of the Galactic interstellar radiation field is higher, particularly in the Galactic center, than previously thought. We have made a calculation of the attenuation of very high energy gamma rays in the Galaxy using this new interstellar radiation field which takes into account its nonuniform spatial and angular distributions. We find that the maximum attenuation occurs around 100 TeV at the level of about 25% for sources located at the Galactic center, and is important for both Galactic and extragalactic sources.

Research Organization:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC02-76SF00515
OSTI ID:
881539
Report Number(s):
SLAC-PUB-11742; ASJOAB; astro-ph/0511149; TRN: US0603163
Journal Information:
Astrophysical Journal, Vol. 640; ISSN 0004-637X
Country of Publication:
United States
Language:
English