Simultaneous multiwavelength observations of Markarian 421 during outburst

© The American Astronomical Society. The VERITAS research was supported by grants from the U.S. Department of Energy, the U.S. National Science Foundation and the Smithsonian Institution, by NSERC in Canada, by Science Foundation Ireland, and by STFC in the U.K. We acknowledge the excellent work of the technical support staff at the FLWO and the collaborating institutions in the construction and operation of the instrument. D. G. and W. C. wish to acknowledge support by NASA through grants NNX06AB96G, NNX08AD76G, and NNX08AX53G. The MAGIC Collaboration thanks the Instituto de Astrofisica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, and Spanish MCINN is gratefully acknowledged. This work was also supported by ETH Research Grant TH 34/043, by the Polish MNiSzW Grant N N203 390834, and by the YIP of the Helmholtz Gemeinschaft. Facilities: MAGIC, VERITAS, FLWO:10m, XMM
We report on the results of two coordinated multiwavelength campaigns that focused on the blazar Markarian 421 during its 2006 and 2008 outbursts. These campaigns obtained UV and X-ray data using the XMM-Newton satellite, while the gamma-ray data were obtained utilizing three imaging atmospheric Cerenkov telescopes, the Whipple 10 m telescope and VERITAS, both based in Arizona, as well as the MAGIC telescope, based on La Palma in the Canary Islands. The coordinated effort between the gamma-ray groups allowed for truly simultaneous data in UV/X-ray/gamma-ray wavelengths during a significant portion of the XMM-Newton observations. This simultaneous coverage allowed for a reliable search for correlations between UV, X-ray, and gamma-ray variability over the course of the observations. Investigations of spectral hysteresis and modeling of the spectral energy distributions are also presented.
U.S. Department of Energy
U.S. National Science Foundation
Smithsonian Institution
NSERC in Canada
Science Foundation Ireland
STFC, U.K
NASA
ETH
Polish MNiSzW
Helmholtz Gemeinschaft
Depto. de Estructura de la Materia, Física Térmica y Electrónica
Fac. de Ciencias Físicas
TRUE
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