SIMULTANEOUS MULTIWAVELENGTH OBSERVATIONS OF MARKARIAN 421 DURING OUTBURST

Abstract

We report on the results of two coordinated multiwavelength campaigns that\nfocused on the blazar Markarian 421 during its 2006 and 2008 outbursts. These\ncampaigns obtained UV and X-ray data using the XMM-Newton satellite, while the\ngamma-ray data were obtained utilizing three imaging atmospheric Cerenkov\ntelescopes, the Whipple 10m telescope and VERITAS, both based in Arizona, as\nwell as the MAGIC telescope, based on La Palma in the Canary Islands. The\ncoordinated effort between the gamma-ray groups allowed for truly simultaneous\ndata in UV/X-ray/gamma-ray wavelengths during a significant portion of the\nXMM-Newton observations. This simultaneous coverage allowed for a reliable\nsearch for correlations between UV, X-ray and gamma-ray variability over the\ncourse of the observations. Investigations of spectral hysteresis and modeling\nof the spectral energy distributions are also presented.\n