Simultaneous XMM--HESS observations: testing the X-ray--TeV connection in BLLacs

We propose to perform a set of simultaneous XrayTeV observations on 2 TeVblazars in the southern hemisphere. We ask for 2 pointings of 20 and 15 ks each,on 2 consecutive XMM revolutions, matching the H.E.S.S. visibility window. Thisstrategy maximizes the simultaneous coverage (45hrs),to sample the shortestvariability timescales, and will allow to observe the source in 2 differentstates, as given by the characteristics flaring timescale of TeV blazars (one tofew days). Our goal is to strongly test and constrain the emission modelsstudying with unprecedented detail the changes in the particle distribution onthese two scales, shedding light onto the acceleration mechanism and allowing todisentangle EBL absorption effects from the blazar intrinsic TeV spectra. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]