Title: “Disk, corona, jet connection in black hole X-ray binaries using reverberation mapping”

Seminar by Jingyi Wang, PhD student (MIT Kavli Institute for Astrophysics and Space Research, Cambridge)

Wednesday 8th of June 2022, 14:15 p.m

Google Meet Link: https://meet.google.com/ots-rija-hyc

Abstract: “Black holes tell us about accretion and ejection physics in the strongest gravity regime in the Universe. Reverberation mapping is a tool for probing those compact regions, in which X-ray light echoes off the accretion disk near the innermost stable circular orbit. The NICER Observatory is revolutionizing reverberation mapping of the inner accretion disks of black hole X-ray binaries in outburst. In this talk, I will present the discovery of reverberation lags in 7 new black hole transients, increasing our total sample to 10 sources. In particular, I will present our key finding that the reverberation lags get longer during the hard-to-soft state transition when a ballistic radio jet is launched. This may suggest an increase in the size of the X-ray emitting region, possibly due to an expanding corona. I will also present the modeling results of NICER spectra and time lags, using the reverberation model Reltrans for MAXI J1820+070, and put these results into the context of other multi-wavelength approaches to understanding the disk-corona-jet connection in black hole transients.”