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 3.8 m telescope was ~ 1.5 TeV. 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.
Astronomy and Astrophysics
- Pub Date:
- March 1999
- GAMMA RAYS: OBSERVATIONS;
- GALAXIES: BL LACERTAE OBJECTS: INDIVIDUAL: PKS0548-322;
- 7 pages + 3 figures. Accepted by Astron. and Astrophys