Cooling a Hot Disk Around a Supermassive Black Hole by a Star
  If a supermassive black hole resides in the centers of galaxies, there are several effects expected to be observed. It is likely that accretion disks are around the supermassive black hole. Stellar interactions with the accretion flows around the supermassive black hole play a role in that an flying-by star may cool a hot accretion disk as a result of Comptonization. It is shown that the Comptonization of the stellar emission will take place in a hot accretion disk such as the ADAFs around the supermassive black hole and become a relatively important source of the accretion disk cooling when the mass accretion rate is low, and stars are passing outer parts of the hot accretion disk. We suggest that such a stellar cooling can be observed in the radio frequency regime since synchrotron luminosity of the ADAFs depends strongly on the electron temperature and occurs much more frequently than a tidal disruption event. 
Heon-Young Chang (Korea Institute for Advanced Study, Seoul, KOREA)