E. Aliu

SIMULTANEOUS MULTIWAVELENGTH OBSERVATIONS OF THE BLAZAR 1ES 1959+650 AT A LOW TeV FLUX

We present the resultsfroma multiwavelength campaignonthe TeVblazar1ES 1959+650, performed in2006May. Data from the optical, UV, soft- and hard-X-ray, and very high energy (VHE) gamma-ray (E > 100 GeV) bands were obtained with the Suzaku and Swift satellites, the MAGIC telescope, and other ground-based facilities. The source spectral energy distribution (SED), derived from Suzaku and MAGIC observations at the end of 2006 May, shows the usual double hump shape, with the synchrotron peak at a higher flux level than the Compton peak. With respect to historicalvalues,duringourcampaignthe sourceexhibiteda relatively highstateinX-raysand optical, while inthe VHEbanditwasatoneof thelowestlevelsofarrecorded.Wealsomonitoredthesourceforfluxspectralvariability onatimewindowof 10daysintheoptical-UVandX-raybandsand7daysintheVHEband.Thesourcevariesmorein the X-ray than in the optical band, with the 2Y10 keV X-ray flux varying by a factor of � 2. The synchrotron peak is locatedintheX-raybandandmovestohigherenergiesasthesourcegetsbrighter,withtheX-rayfluxesaboveitvarying more rapidly than the X-ray fluxes at lower energies. The variability behavior observed in the X-ray band cannot be