The role of GLAST in multiwavelength observations of bright TeV blazars

The TeV blazars Mrk 421, Mrk 501, PSK 2155-304 and 1ES1959+650 are among the brightest known blazars, yet the existing experimental set of data does not allow one to make unambiguous state- ments about the physical mechanisms responsible for the electromagnetic emission. The lack of sensitive coverage in the energy range 1 MeV to 500 GeV (up to 2004), and the scarce truly simultaneous data result in a big inter-model and intra-model degeneracy. The LAT instrument on board of the GLAST satellite, which will start operation at the beginning of 2008, aims to perform gamma-ray astronomy in the energy range 20 MeV to 300 GeV. The sensitivity of LAT is about 25 times better than its predecessor, EGRET. Together with the enhanced sensitivity of the current generation of Imaging Air Cherenkov Telescopes (IACTs) in the energy range 100 GeV 500 GeV, LAT observations offer unprecedented capabilities to study the high energy emission of these objects in both quiescent and flaring state.