THE PHYSICAL PROCESS RESPONSIBLE FOR THE SO-CALLED OPTICAL CHANGING-LOOK AGN I.E. SOURCES IN WHICH THE BROAD LINES PRODUCED BY MATERIAL SURROUNDING THE SUPERMASSIVE BLACK HOLE APPEAR OR DISAPPEAR IS STILL POORLY UNDERSTOOD. OUR GROUP RECENTLY CAUGHT ONE OF THESE RARE OBJECTS THE NEARBY UNOBSCURED TYPE-2 AGN 1ES 1927+654 IN THE ACT OF DEVELOPING BROAD LINES. THIS IS THE FIRST CASE WHERE THE LAG BETWEEN THE CHANGE IN CONTINUUM AND IN BROAD LINE EMISSION OF A CHANGING-LOOK AGN HAS BEEN TEMPORALLY RESOLVED. OUR X-RAY MONITORING CAMPAIGN WHICH INCLUDES . 190 NICER OBSERVATIONS 13 SWIFT/XRT AND TWO SIMULTANEOUS XMM-NEWTON/ NUSTAR OBSERVATIONS HAS SHOWN AN EXTREMELY PECULIAR X-RAY EMISSION. THE X-RAY SPECTRUM IS IN FACT SUPERSOFT BEING DOMINATED BY A BLACKBODY COMPONENT WITH ONLY A WEAK CONTRIBUTION FROM A CUTOFF POWERLAW WITH G . 3.5 AND A CUTOFF ENERGY AT ECUT . 3 KEV WHICH SUGGESTS THAT THE X-RAY CORONA WAS DESTROYED DURING THE OPTICAL-UV TRANSIENT EVENT. THE X-RAYS ARE ALSO EXTREMELY VARIABLE (. 2 ORDERS OF MAGNITUDE IN .8 HOURS AND . 4 ORDERS OF MAGNITUDE IN .100DAYS). OUR OBSERVATIONS HAVE FINALLY SHOWN A RECENT HARDENING OF THE XRAY EMISSION INDICATIVE OF A RE-CREATION OF THE X-RAY CORONA.
$65,657FY2020National Aeronautics and Space AdministrationNASA
George Mason University, Fairfax VA