Andrea Boller ETH, Institut fuer Teilchenphysik

MAGIC and Multi-Frequency Observations of the nearby Blazar Markarian 421 (pdf)

The MAGIC system consists of two Imaging Atmospheric Cherenkov Telescopes, located at 2200 m above sea level on the Canary Island of La Palma. Its aim is to detect particle showers induced by celestial very high energy gamma rays (E > tens of GeV), using the Cherenkov radiation. Blazars, a subclass of Active Galactic Nuclei, are among the targets of MAGIC. For strong and well established Blazars, MAGIC is frequently participating in synchronized multiwavelength (MWL) campaigns, organized on long terms between many observatories worldwide. The exceptional low energy threshold of 50 GeV makes MAGIC the best suited Cherenkov telescope to provide an overlap between ground based and space born gamma-ray telescopes. In this talk I present the results of 2009 MWL observations of the Blazar Markarian 421, one of the strongest TeV sources of the northern sky.