Title: Observation of Mrk 421 with INTEGRAL
Proposal ID: 0120200
Subject category: Extragalactic Object
Principal investigator: Lichti
Institute: Max-Planck-Institut f|r extraterrestrische Physik
Abstract
Mrk 421 belonging to the BL Lac type of AGNs can be the brightest TeV gamma-ray source in the sky. The
spectrum of these sources is characterised by two smooth broadband emission components which peak in the
IR/X-ray band and at TeV energies. The transition region falls exactly into the energy range of the two main
instruments of INTEGRAL.
It is proposed to observe Mrk 421 with INTEGRAL twice, once when it is in a
quiescent state and a second time when it is active. An alert for such an observation will be issued by
Cherenkov telescopes. If Mrk 421 is entering a high state an observation of it by INTEGRAL shall be
performed (ToO proposal). Since one learns most about the emission processes from multiwavelength
observations it is planned to organize such simultaneous observations from radio wavelengths up to TeV
energies.