Title: MeV-TeV Blazars

Title: MeV-TeV Blazars

Proposal ID: 0120117
Subject category: Extragalactic Object
Principal investigator: Ghisellini
Institute: Osservatorio Astronomico di Brera

Abstract

We propose (up to 3) ToO INTEGRAL observations of BL Lac objects triggered by their detection in the TeV band by ground based Cherenkov telescopes. This ensures a very high state in the hard X-ray band. In fact the peak of the synchrotron spectrum, a crucial parameter for all models, is expected to be in the IBIS range. The proposed observations can establish if the same population of electrons emits by the synchrotron process in X-rays and by the inverse Compton mechanism at TeV energies. We will enhance our understanding of particle acceleration process when working at its extreme. The comparision of spectral shapes in the hard X-ray (possibly up to the MeV band) and TeV (and sub TeV) bands will establish the importance of the photon-photon absorption process due to the cosmic IR background, constraining its poorly known level. Being an imaging instrument, IBIS will be free from contamination problems, that have affected several observations made by the PDS instrument onboard BeppoSAX.