Optical Variability of the Blazar BL Lacertae

Meredith Tanguay

Advisor: Dr. Thomas Balonek

BL Lacertae, a complex, highly variable blazar, has been observed at optical wavelengths for 13 years with Colgate University’s Foggy Bottom Observatory 16” telescope equipped with a CCD camera. Image calibration and reduction is accomplished in IRAF with the aid of Colgate-specific scripts. Investigation of the variability allows us to probe the physical processes of this object, the prototype for the BL Lac category. This study focuses on R-filter CCD data taken between summer 2000 and spring 2002. This data set contains over 1200 measurements on 132 nights, including several nights of micro-variability and one night of multi-filter observations. During this period BL Lac varied between R = 14.4 and 12.4; at least two distinct flares were observed. The variability timescale and profile of these flares during this outburst period are examined in both magnitude and flux.