Discovery of very high energy gamma-ray emission from the low-frequency peaked BL Lac object BL Lacertae

Preprint
Publisher Website
Google Scholar
  • 5 March 2007
Abstract
The low-frequency peaked BL Lac (LBL) object BL Lacertae was observed with the MAGIC telescope from August to December 2005 (22.2 hrs), and from July to September 2006 (26.0 hrs). A very high energy (VHE) gamma-ray signal was discovered with a 5.1 sigma excess in the 2005 data. Above 200 GeV, an integral flux of (0.6+-0.2)x10^{-11} cm^{-2} s^{-1} was measured, corresponding to approximate by 3 of the Crab flux. The differential spectrum between 150 and 900 GeV is rather steep, with a photon index of -3.6+-0.5. For the first time, a clear detection of VHE gamma-ray emission from an LBL object was obtained with a signal below previous upper limits. During the observation, the light curve shows no large fluctuation. On the contrary, the 2006 data show no significant excess. This drop in flux follows the observed trend in optical activity.

This publication has 0 references indexed in Scilit: