tidal disruption events

Tidal disruption events

Fundamental timescales relevant to black hole accretion – dynamical, thermal, viscous – should scale linearly with the black hole mass. Through X-ray binary systems of stellar-mass black holes in the Milky Way, changes in accretion state over weeks to months have been extremely well-characterized in X-rays. We expect these same changes to happen over thousands to millions of years (far beyond human-observable timescales) for the supermassive black holes (SMBHs) at centers of galaxies, whose accretion histories are tied to galaxy formation and growth.

A class of transients called tidal disruption events, where a star is torn apart by a supermassive black hole, allow us to watch an accretion disk form and evolve around an SMBH in real time. I am particularly interested in TDEs that undergo state transitions, and how we can use their observational properties to measure the mass of the supermassive black hole.

Here is an example of some of my recent work on the TDE AT2019teq, which formed an corona of billion-degree plasma in the years post discovery and shows exceptional variability:

GIF credit: NASA GSFC