Evolution of a Relativistic Outflow and X-ray Corona in the Extreme Changing-Look AGN 1ES 1927+654

1ES 1927+654 is an AGN like no other. This system underwent a “changing-look” event in 2018, where broad emission lines appeared in its optical spectrum (see Trakhtenbrot+19). However, the peculiarities of 1ES 1927+654 are most prominent in the X-ray part of the spectrum–1ES 1927+654 is the first known AGN where we’ve witnessed the destruction of the X-ray corona and the disappearance of the ubiquitous power law component of the X-ray spectrum (see Ricci+20). This unique X-ray behavior prompted a massive X-ray follow-up campaign, including over 500 NICER observations and 7 simultaneous XMM-Newton/NuSTAR observations. We analyzed the X-ray spectral evolution over the entire outburst, and found that, despite the extreme changes to the X-ray spectrum initially, the X-ray spectrum returned to its pre-outburst state is just 3 years! In addition, we provided a new physical model for a mysterious, broad 1 keV line that was extremely prominent in the early X-ray spectra. This model, called xillverTDE, is a thermal reflection model for a single-temperature blackbody irradiating spectrum. Using this model, we infer that there are fast outflows launched from the inner accretion flow, that might look something like the schematic below. We are now working to apply this same model to other super-Eddington accretors that show fast outflow features in their X-ray spectra.