Observations of gamma ray emission from Markarian 501 by the VERITAS Observatory

Markarian 501 is a blazar-type galaxy with an active galactic nucleus (AGN) at a red shift of 0.0337. In blazar type AGN, jets emerging from the vicinity of the core supermassive black hole are chance aligned with the observer. Markarian 501 was observed by the VERITAS TeV gamma ray telescope array between April and June 2009. A total of 1116 minutes of B grade (or better) weather data was selected for this analysis. In this data set Markarian 501 was detected at a significance level of 24.1 sigma, corresponding to a rate of 0.428 gamma-rays/minute. In this talk I will describe the results of this analysis and compare it to previous observations of VHE emission from Markarian 501.