MAGIC CollaborationParedes i Poy, Josep MariaRibó Gomis, MarcBosch i Ramon, Valentí2020-02-132020-02-132009-09-260004-637Xhttps://hdl.handle.net/2445/150146We 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.10 p.application/pdfeng(c) American Astronomical Society, 2009Raigs XGalàxiesRaigs gammaObservacions astronòmiquesX-raysGalaxiesGamma raysAstronomical observationsinfo:eu-repo/semantics/article5708942020-02-13info:eu-repo/semantics/openAccess