Very High Energy Gamma Rays from PKS 2155-304
Abstract
The close X-ray-selected BL Lac PKS 2155-304 has been observed using the University of Durham Mark 6 very high energy (VHE) gamma-ray telescope during 1996 September/October/November and 1997 October/November. VHE gamma rays with energy more than 300 GeV were detected from this object with a time-averaged integral flux of (4.2+/-0.7stat+/-2.0sys)×10-11 cm-2 s-1. There is evidence for VHE gamma-ray emission during our observations in 1996 September and 1997 October/November, with the strongest emission being detected in 1997 November, when the object was producing the largest flux ever recorded in high-energy X-rays and it was detected as a source of gamma rays of energy greater than 100 MeV. The VHE and X-ray fluxes show evidence of a correlation.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1999
- DOI:
- 10.1086/306862
- arXiv:
- arXiv:astro-ph/9810209
- Bibcode:
- 1999ApJ...513..161C
- Keywords:
-
- BL LACERTAE OBJECTS: INDIVIDUAL (PKS 2155-304);
- GALAXIES: ACTIVE;
- GAMMA RAYS: OBSERVATIONS;
- BL Lacertae objects: individual (PKS 2155-304);
- Galaxies: Active;
- Gamma Rays: Observations;
- Astrophysics
- E-Print:
- 14 pages, 6 figures, accepted for publication in Ap. J