TeV gamma-ray observations of three X-ray selected BL Lacs
نویسنده
چکیده
Despite extensive surveys of extragalactic TeV gamma-ray candidates only 3 sources have so far been detected. All three are northern hemisphere objects and all three are low-redshift X-ray selected BL Lacs (XBLs). In this paper we present the results of observations of the three nearest southern hemisphere XBLs (PKS0548−322, PKS2005−489 and PKS2155−304) with the CANGAROO 3.8m imaging telescope. During the period of observation we estimate that the threshold of the 3.8m telescope was ∼1.5TeV. Searches for both steady and short timescale emission have been performed for each source. Additionally, we are able to monitor the X-ray state of each source on a daily basis and we have made contemporaneous measurements of optical activity for PKS0548−322 and PKS2155−304.
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