1640027

We propose a 500 ks target of opportunity INTEGRAL observation of a blazar in outburst as detected by the FACT blazar-monitoring program at TeV energies supplemented by pre-outburst snapshots and follow-up monitoring with Swift. Bright TeV gamma-ray flares have been detected frequently from blazars such as Mrk 501 Mrk 421 and 1 ES 1959+650 but time-resolved information of the multiwavelength spectra covering the complete outburst are rare. Leptonic models for TeV flares predict simultaneous flux increases in the X-ray and in the gamma-ray band while lepto-hadronic models show a complex variability pattern in these energy bands depending on the dominant process responsible for the gamma-ray emission. Other types of TeV flares challenge current models: orphan flares which show variability in gamma-rays only and flares with time lags between both bands. Most existing data sets of flaring behaviors lack detailed pre- and post-flare light curves and spectra as well as continuous TeV monitoring. The here proposed observations 1) are triggered on bright gamma-ray flares 2) yield simultaneous data in the optical/UV X-ray GeV- and very-high gamma-ray bands and 3) contain pre- and post-flare source state information. This type of ToO observations are feasible with the FACT blazar-monitoring program. [truncated! Please see actual data for full text]