Detection of Sub-TeV gamma-rays from the Galactic Center with the CANGAROO-II telescope

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

DOI:https://doi.org/10.1063/1.1878437· OSTI ID:20630528

Tsuchiya, Ken'ichi ^[1]

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1. ICRR, University of Tokyo, 5-1-5 Kashiwanoba, Kashiwa city, Chiba 277-8582 (Japan)

The Galactic Center has been observed with the CANGAROO-II imaging atmospheric Cherenkov telescope in 2001 and 2002. We detected a statistically significant excess at energies greater than 250GeV. This is the first detection of sub-TeV gamma rays from the Galactic Center region. The signal direction is consistent with the Galactic Center, which includes the massive black hole Sgr A* and supernova remnant Sgr A East. The resultant flux is 1 order of magnitude lower than that of the Crab Nebula at 1 TeV. The differential flux has a steep spectrum and the power law index is observed to be -4.6 {+-} 0.5, although it could flatten to -3.4 if the uncertainty in energy determination is included. Here, the analysis for reduction of night sky background effects and the radiation mechanism of sub-TeV gamma rays are reported. The most probable radiation mechanism is {pi}0 decays. The maximum energy of the inferred cosmic rays is 1-3 TeV and the total cosmic-ray luminosity corresponds to 1 {approx} 10 supernova remnants. We also obtain an upper limit on the cold dark matter density in the galactic halo.

• OSTI ID: 20630528
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 745; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BLACK HOLES
CHERENKOV COUNTERS
COSMIC GAMMA SOURCES
COSMIC RAY DETECTION
CRAB NEBULA
GAMMA ASTRONOMY
GAMMA RADIATION
LUMINOSITY
NONLUMINOUS MATTER
PARTICLE DECAY
PIONS NEUTRAL
TELESCOPE COUNTERS
TEV RANGE