High-energy emission from tidal disruption events in active galactic nuclei. (arXiv:2101.02290v2 [astro-ph.HE] UPDATED)

High-energy emission from tidal disruption events in active galactic nuclei. (arXiv:2101.02290v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Chan_C/0/1/0/all/0/1">Chi-Ho Chan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piran_T/0/1/0/all/0/1">Tsvi Piran</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krolik_J/0/1/0/all/0/1">Julian H. Krolik</a>

Tidal disruption events (TDEs) taking place in active galactic nuclei (AGNs)
are different from ordinary TDEs. In these events, the returning tidal debris
stream drills through the pre-existing AGN accretion disk near the stream
pericenter, destroying the inner disk in the process, and then intersects with
the disk a second time at radii ranging from a few to hundreds of times the
pericenter distance. The debris dynamics of such TDEs, and hence their
appearance, are distinct from ordinary TDEs. Here we explore the observational
signatures of this “second impact” of the stream with the disk. Strong shocks
form as the dilute stream is stopped by the denser disk. Compton cooling of the
shocked material produces hard X-rays, even soft gamma-rays, with most of the
energy emitted between ~10 keV and 1 MeV. The luminosity follows the
mass-return rate, peaking between ~$10^{42}$ and $10^{44}$ erg/s. The X-ray
hardness and the smoothness of the light curve provide possible means for
distinguishing the second impact from ordinary AGN flares, which exhibit softer
spectra and more irregular light curves.

Tidal disruption events (TDEs) taking place in active galactic nuclei (AGNs)
are different from ordinary TDEs. In these events, the returning tidal debris
stream drills through the pre-existing AGN accretion disk near the stream
pericenter, destroying the inner disk in the process, and then intersects with
the disk a second time at radii ranging from a few to hundreds of times the
pericenter distance. The debris dynamics of such TDEs, and hence their
appearance, are distinct from ordinary TDEs. Here we explore the observational
signatures of this “second impact” of the stream with the disk. Strong shocks
form as the dilute stream is stopped by the denser disk. Compton cooling of the
shocked material produces hard X-rays, even soft gamma-rays, with most of the
energy emitted between ~10 keV and 1 MeV. The luminosity follows the
mass-return rate, peaking between ~$10^{42}$ and $10^{44}$ erg/s. The X-ray
hardness and the smoothness of the light curve provide possible means for
distinguishing the second impact from ordinary AGN flares, which exhibit softer
spectra and more irregular light curves.

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