Exploring changing-look AGNs through the QPE analogy\: the case of Mrk 590

Mrk 590 is one of the best monitored changinglook AGN. After a decay duringwhich the continuum dimmed and the optical broad line disappeared together withthe soft Xray excess, Mrk 590 is now awakening and broad line and soft excesshave reemerged. We request two relatively inexpensive (25 ks) observations,that will be spaced by about 6 months, to follow the Xray spectral evolutionduring the current rise. The recently discovered QPE phenomenon (Miniutti et al2019, Nature) may be invoked to account for the spectacular variability of thisand other changinglook AGNs. If so, the analogy predicts that the soft Xrayexcess should increase in strength and temperature during the rise. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]