Abstract for Proposal 094004

Radio-quiet AGN in outburst

XMM-Newton observations of Seyfert galaxies established outbursts of radio-quiet AGNs as a still poorly explored discovery space for AGN physics with an enormous potential to learn: NGC 1566, HE1136-2304 and NGC 2617 are rare and extreme changing-look AGNs tracing rapid changes in accretion and/or corona physics including the launching of new outflows. Sources like GSN 069 very likely traces an AGN disturbed by a tidal disruption event. We propose two 80ks simultaneous XMM-Newton(EPIC&RGS)/NuSTAR observations accompanied by optical spectroscopy of the next suited AGN outburst(s). They will allow tracing the accretion physics, the launching of winds and outflows, the spectral complexity connected with dramatic emission-line changes and possibly the elusive tidal disruption events.

Details on Observing Strategy and Trigger Criteria
1. Either (a) an extreme increase in brightness by a factor of 15 in X-rays, or two magnitudes in the optical (where AGN are known to vary less); or (b) an event which shows a systematic rapid increase in one waveband. 2. We will ask for a short Swift observation(s) to verify that a candidate has an X-ray flux which is a factor of $>15$ higher than the highest/quiescent flux found by previous X-ray missions. 3. When an outburst is confirmed and only then, we will trigger a 80ks simultaneous XMM-Newton & NuSTAR observation. The reaction time is about one week. In addition, we will take a quasi-simultaneous observation with a large optical telescope; SALT (in the South) or the Hobby-Eberly Telescope (HET, in the North) are accessible to us. 4. In case the Swift monitoring reveals an X-ray spectral change, we will trigger our second XMM-Newton &NuSTAR observation.