Discovery of Diffuse TeV Gamma Ray Emission from the Galactic Plane using Milagro Detector

Journal Article · Mon Feb 21 04:00:00 EST 2005 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.1878415· OSTI ID:20630520

Fleysher, Roman ^[1]

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1. Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)

Milagro is a water Cherenkov extensive air shower array that continuously views the entire overhead sky and is sensitive to gamma rays with energies near 1 TeV. Prior to this work, EGRET had observed the highest energy gamma rays from the Galactic plane. In the direction of the inner Galaxy and at energies between 1 GeV and 30 GeV, EGRET measured a gamma-ray spectral index of approximately {alpha}{gamma} = 2.4, harder than the cosmic-ray spectrum. The shape and intensity of the spectrum beyond EGRET energies is sensitive to the production and propagation of cosmic rays. Here we report the detection of the TeV gamma rays from the region of the Milagro inner Galaxy ({+-}5 deg. Galactic latitude and (40 deg., 100 deg.) Galactic longitude) with a significance of 5{sigma}. The integral flux is estimated to be {phi}{gamma}(E > 1TeV) = (5.7 {+-} 2.0) {center_dot} 10-10 (ster-1cm-2sec-1) assuming a differential power law spectral index of 2.7 and an EGRET-like source distribution. Comparison with EGRET's data from the same part of the Galaxy may be used to constrain models of cosmic-ray production in the Galaxy.

• OSTI ID: 20630520
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 745; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
COMPARATIVE EVALUATIONS
COSMIC PHOTONS
COSMIC RAY DETECTION
COSMIC RAY PROPAGATION
DISTRIBUTION
ENERGY SPECTRA
EXTENSIVE AIR SHOWERS
GALAXIES
GAMMA ASTRONOMY
GAMMA RADIATION
GEV RANGE
PHOTON EMISSION
TELESCOPE COUNTERS
TEV RANGE
WATER