Evidence for TeV gamma ray emission from Cassiopeia A
نویسنده
چکیده
With the HEGRA stereoscopic system of imaging atmospheric Cherenkov telescopes, TeV γ-ray emission was detected from the Supernova remnant Cassiopeia A for the first time. The detection has a statistical significance of 5σ. A flux of (5.8 ± 1.2stat ± 1.2syst) × 10−9ph m−2s−1 above 1 TeV is derived. The spectral distribution is consistent with a power law with a differential spectral index −2.5 ± 0.4stat ± 0.1syst between 1 and 10 TeV. The signal has a Crab-like spectrum, but only 3% of its flux. With this detection, the HEGRA system has demonstrated its currently unique ability to detect TeV γ-ray emission at the “centiCrab” scale. The detection of TeV γ-rays indicates that Cassiopeia A is a site of CR acceleration for particles – either nucleons or electrons – with multi-TeV energies. However, the assignment of the γ-ray emission to either or both particle populations relies on modeling. We discuss some important aspects in this paper.
منابع مشابه
Evidence for TeV gamma ray emission from Cassiopeia A
232 hours of data were accumulated from 1997 to 1999, using the HEGRA Stereoscopic Cherenkov Telescope System to observe the supernova remnant Cassiopeia A. TeV γ-ray emission was detected at the 5σ level, and a flux of (5.8± 1.2stat ± 1.2syst)× 10phms above 1TeV was derived. The spectral distribution is consistent with a power law with a differential spectral index of −2.5± 0.4stat ± 0.1syst b...
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