VERITAS observation of Markarian 421 flaring activity

Abstract

Markarian 421 is one of the brightest BL-Lac objects in gamma-rays in the northern hemisphere. Because of its brightness, the source has been the focus of several coordinated multi-wavelength (MWL) campaigns designed to study the physical processes responsible for the non-thermal continuum emission. The blazar monitoring program of VERITAS recently received a ToO during a strong flaring event by Markarian 421 in February 2010. The source was seen at flux level of approximately 8 Crab units and exhibited spectral evolution and variability features. A multi-wavelength campaign with other MWL partners was udndertaken. Results on past and recent flaring events are presented.