CANGAROO-III Observations of the 2006 Outburst of PKS 2155-304
Date
2008
Authors
Sakamoto, Y
Nishijima, K
Mizukami, T
Yamazaki, E
Kushida, J
Enomoto, R
Ohishi, M
Bicknell, Geoffrey
Clay, Roger W
Edwards, Philip G
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Publisher
IOP Publishing
Abstract
We have used the CANGAROO-III imaging atmospheric Cerenkov telescopes to observe the high-frequency-peaked BL Lacertae (HBL) object PKS 2155-304 between 2006 July 28 (MJD 53,944) and August 2, triggered by the H.E.S.S. report that the source was in a high state of TeV gamma-ray emission. A signal was detected at the 4.8 σ level in an effective live time of 25.1 hr during the outburst period. The flux of very high energy gamma rays from the CANGAROO-III observations shows variability on the timescale of less than a few hours. The averaged integral flux above 660 GeV is (1.6 ± 0.3stat ± 0.5syst) × 10-11 cm-2 s -1, which corresponds to ∼45% of the flux observed from the Crab Nebula. Follow-up observations between August 17 (MJD 53,964) and 25 indicate that the source activity had decreased.
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Keywords
Keywords: BL Lacertae objects: individual (PKS 2155-304); Galaxies: active; Gamma rays: observations
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Source
Astrophysical Journal, The
Type
Journal article
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2037-12-31