NICER observation list: Target ID 570501

After a 10-year hiatus, Mrk 590 has partially re-ignited, with repeated major X-ray and UV flare-ups captured by Swift monitoring. We wish to seize this rare opportunity to document the onset of AGN activity as it occurs, since this can lead to significant insight on the long-standing issue of how AGNs are triggered and fueled. We will use approved Swift XRT monitoring to trigger up to 4 single-visit NuSTAR observations, of which up to 3 are joint with XMM (or NICER). Together, these data are needed to determine if a standard thin accretion disk is being built up as the AGN turns on (and then characterize this event) or if alternate physics are at play.