NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
EGRET observations of gamma-ray emission from the interstellar gas in OrionThe high-energy diffuse gamma-ray emission from the interstellar gas in Orion was studied using observations from the Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory (CGRO) and radio surveys of the H I and CO emission. The good correlation of the gamma-ray emission with the atomic and molecular gas permits determination of the gamma-ray emissivity per nucleon in the interstellar medium and the molecular mass calibrating ratio N(H2)/W(sub co) in Orion. The integral gamma-ray emissivity is (1.7 +/- 0.1) x 10(exp -26)/s/sr for E greater than 100 MeV, in good agreement with expectations from studies of the diffuse emission on larger scales. The N(H2)/W(sub co) ratio is (1.06 +/- 0.14) x 10(exp 20)/sq cm/(K km/s), approximately 40% less than the commonly adopted Galactic average. We find no evidence for variations of the cosmic-ray density or N(H2)/W(sub co) ratio in Orion at the sensitivity and resolution of EGRET.
Document ID
19950044575
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Digel, S. W.
(Center for Astrophysics, Cambridge, MA United States)
Hunter, S. D.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mukherjee, R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 16, 2013
Publication Date
March 1, 1995
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 441
Issue: 1
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
95A76174
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available