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Title: FERMI LAT OBSERVATION OF DIFFUSE GAMMA RAYS PRODUCED THROUGH INTERACTIONS BETWEEN LOCAL INTERSTELLAR MATTER AND HIGH-ENERGY COSMIC RAYS

Abstract

Observations by the Large Area Telescope (LAT) on the Fermi mission of diffuse gamma-rays in a mid-latitude region in the third quadrant (Galactic longitude l from 200 deg. to 260 deg. and latitude |b| from 22 deg. to 60 deg.) are reported. The region contains no known large molecular cloud and most of the atomic hydrogen is within 1 kpc of the solar system. The contributions of gamma-ray point sources and inverse Compton scattering are estimated and subtracted. The residual gamma-ray intensity exhibits a linear correlation with the atomic gas column density in energy from 100 MeV to 10 GeV. The measured integrated gamma-ray emissivity is (1.63 +- 0.05) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} and (0.66 +- 0.02) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} above 100 MeV and above 300 MeV, respectively, with an additional systematic error of {approx}10%. The differential emissivity from 100 MeV to 10 GeV agrees with calculations based on cosmic ray spectra consistent with those directly measured, at the 10% level. The results obtained indicate that cosmic ray nuclei spectra within 1 kpc from the solar system in regions studied are close to the local interstellar spectra inferred frommore » direct measurements at the Earth within {approx}10%.« less

Authors:
 [1]; ;  [2]
  1. Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
  2. W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
Publication Date:
OSTI Identifier:
21371917
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 703; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/703/2/1249; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPTON EFFECT; COSMIC RADIATION; EMISSIVITY; GAMMA RADIATION; GEV RANGE 01-10; HYDROGEN; MEV RANGE 100-1000; POINT SOURCES; SOLAR SYSTEM; SPECTRA; TELESCOPES; BASIC INTERACTIONS; ELASTIC SCATTERING; ELECTROMAGNETIC INTERACTIONS; ELECTROMAGNETIC RADIATION; ELEMENTS; ENERGY RANGE; GEV RANGE; INTERACTIONS; IONIZING RADIATIONS; MEV RANGE; NONMETALS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; RADIATION SOURCES; RADIATIONS; SCATTERING; SURFACE PROPERTIES

Citation Formats

Abdo, A A, Ackermann, M, and Ajello, M. FERMI LAT OBSERVATION OF DIFFUSE GAMMA RAYS PRODUCED THROUGH INTERACTIONS BETWEEN LOCAL INTERSTELLAR MATTER AND HIGH-ENERGY COSMIC RAYS. United States: N. p., 2009. Web. doi:10.1088/0004-637X/703/2/1249.
Abdo, A A, Ackermann, M, & Ajello, M. FERMI LAT OBSERVATION OF DIFFUSE GAMMA RAYS PRODUCED THROUGH INTERACTIONS BETWEEN LOCAL INTERSTELLAR MATTER AND HIGH-ENERGY COSMIC RAYS. United States. doi:10.1088/0004-637X/703/2/1249.
Abdo, A A, Ackermann, M, and Ajello, M. Thu . "FERMI LAT OBSERVATION OF DIFFUSE GAMMA RAYS PRODUCED THROUGH INTERACTIONS BETWEEN LOCAL INTERSTELLAR MATTER AND HIGH-ENERGY COSMIC RAYS". United States. doi:10.1088/0004-637X/703/2/1249.
@article{osti_21371917,
title = {FERMI LAT OBSERVATION OF DIFFUSE GAMMA RAYS PRODUCED THROUGH INTERACTIONS BETWEEN LOCAL INTERSTELLAR MATTER AND HIGH-ENERGY COSMIC RAYS},
author = {Abdo, A A and Ackermann, M and Ajello, M},
abstractNote = {Observations by the Large Area Telescope (LAT) on the Fermi mission of diffuse gamma-rays in a mid-latitude region in the third quadrant (Galactic longitude l from 200 deg. to 260 deg. and latitude |b| from 22 deg. to 60 deg.) are reported. The region contains no known large molecular cloud and most of the atomic hydrogen is within 1 kpc of the solar system. The contributions of gamma-ray point sources and inverse Compton scattering are estimated and subtracted. The residual gamma-ray intensity exhibits a linear correlation with the atomic gas column density in energy from 100 MeV to 10 GeV. The measured integrated gamma-ray emissivity is (1.63 +- 0.05) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} and (0.66 +- 0.02) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} above 100 MeV and above 300 MeV, respectively, with an additional systematic error of {approx}10%. The differential emissivity from 100 MeV to 10 GeV agrees with calculations based on cosmic ray spectra consistent with those directly measured, at the 10% level. The results obtained indicate that cosmic ray nuclei spectra within 1 kpc from the solar system in regions studied are close to the local interstellar spectra inferred from direct measurements at the Earth within {approx}10%.},
doi = {10.1088/0004-637X/703/2/1249},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 703,
place = {United States},
year = {2009},
month = {10}
}

Works referencing / citing this record:

Cosmic Rays in the Heliosphere: Requirements for Future Observations
journal, August 2012