Study of the Classical TeV Blazars with Fermi

摘要

Despite High Peak BL Lacs (HBL) being observed for tens of years, the existing experimental data set is not sufficient to unambiguously iden-tify the physical mechanisms responsible for the electromagnetic emission. The Fermi-LAT instrument, winch started operation in August 2008, provides "con-tinuous" source coverage with high sensitivity in the band 0.1-100 GeV, which is rather unexplored for HBLs. In particular, the simultaneous observations of HBLs with Fermi-LAT and Imaging Cherenkov Telescopes (IACTs) have the unprecedented capability of resolving the high energy bump on time scales of weeks and shorter for the brightest HBLs, which has the potential of break-ing inter-model and intra-model degeneracies. In order to understand the HBL phenomenom (and blazars in general) we organized multi-frequency campaigns on 3 classical TeV objects: Markarian 421, Markarian 501 and les1959+650. The campaigns lasted several months and allowed us to collect the most complete data set (including the essentially so far un-explored GeV energy region from Fermi-LAT) from those objects up to date. In this manuscript we briefly describe these campaigns and show the combined Fermi-MAGIC spectrum for Mrk421 which, for the first time, covers without gaps the energy range spanning from 0.1 GeV to almost 10 TeV.