X-ray from Outflow-Cloud Interaction and Its Application in Tidal Disruption Events by Jiashi Chen et al. on Monday 21 November

Tidal disruption events (TDEs) may occur in supermassive black holes (SMBHs)

surrounded by clouds. TDEs can generate ultrafast and large opening-angle

outflow with a velocity of $\sim$ 0.01--0.2 c, which will collide with clouds

with time lags depending on outflow velocity and cloud distances. Since the

fraction of the outflow energy transferred into cloud's radiation is

anti-correlated with the cloud density, high density clouds was thought to be

inefficient in generating radiation. In this work, we studied the radiation

from the outflow-cloud interactions for high density clouds, and found that

thermal conduction plays crucial roles in increasing the cloud's radiation. Up

to 10\% of the bow shock energy can be transferred into clouds and gives rise

to X-ray emission with equivalent temperature of $10^{5-6}$ Kelvins due to the

cooling catastrophe. The inverse Compton scattering of TDE UV/optical photons

by relativistic electrons at bow shock generates power-law X-ray spectra with

photon indices $\Gamma\sim 2-3$. This mechanism may account for some TDE

candidates with delayed X-ray emission, and can be examined by delayed radio

and gamma-ray emissions.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.10004v1