Elliptical Accretion Disk as a Model for Tidal Disruption Events

@article{59443,
   author = {Liu, F. K. and Cao, C. Y. and Abramowicz, Marek and Wielgus, M. and Cao, R. and Zhou, Z. Q.},
   article_location = {GB - Spojené království Velké Británie a},
   article_number = {2},
   doi = {http://dx.doi.org/10.3847/1538-4357/abd2b6},
   keywords = {Accretion;black hole physics;Active galaxies;Supermassive black holes;Tidal disruption;Galaxy accretion disks},
   language = {eng},
   issn = {0004-637X},
   journal = {Astrophysical Journal},
   title = {Elliptical Accretion Disk as a Model for Tidal Disruption Events},
   url = {https://iopscience.iop.org/article/10.3847/1538-4357/abd2b6},
   volume = {908},
   year = {2021}
}

TY  - JOUR
ID  - 59443
AU  - Liu, F. K. - Cao, C. Y. - Abramowicz, Marek - Wielgus, M. - Cao, R. - Zhou, Z. Q.
PY  - 2021
TI  - Elliptical Accretion Disk as a Model for Tidal Disruption Events
JF  - Astrophysical Journal
VL  - 908
IS  - 2
SP  - "179-1"-"179-30"
EP  - "179-1"-"179-30"
SN  - 0004637X
KW  - Accretion;black hole physics;Active galaxies;Supermassive black holes;Tidal disruption;Galaxy accretion disks
UR  - https://iopscience.iop.org/article/10.3847/1538-4357/abd2b6
N2  - Elliptical accretion disk models for tidal disruption events (TDEs) have been recently proposed and independently developed by two groups. Although these two models are characterized by a similar geometry, their physical properties differ considerably. In this paper, we further investigate the properties of the elliptical accretion disk of the nearly uniform distribution of eccentricity within the disk plane. Our results show that the elliptical accretion disks have distinctive hydrodynamic structures and spectral energy distributions, associated with TDEs. The soft X-ray photons generated at pericenter and nearby are trapped in the disk and advected around the ellipse because of large electron scattering opacity. They are absorbed and reprocessed into emission lines and low-frequency continuum via recombination and bremsstrahlung emission. Because of the rapid increase of bound-free and free-free opacities with radius, the low-frequency continuum photons become trapped in the disk at large radius and are advected through apocenter and back to the photon-trapping radius. Elliptical accretion disks predict sub-Eddington luminosities and emit mainly at the photon-trapping radius of thousands of Schwarzschild radii with a blackbody spectrum of nearly single temperature of typically about 3 x 10(4) K. Because of the self-regulation, the photon-trapping radius expands and contracts following the rise and fall of accretion rate. The radiation temperature is nearly independent of BH mass and accretion rate and varies weakly with the stellar mass and the viscosity parameter. Our results are well consistent with the observations of optical/UV TDEs.
ER  - 

LIU, F. K., C. Y. CAO, Marek ABRAMOWICZ, M. WIELGUS, R. CAO and Z. Q. ZHOU. Elliptical Accretion Disk as a Model for Tidal Disruption Events. \textit{Astrophysical Journal}. GB - Spojené království Velké Británie a, 2021, vol.~908, No~2, p.~''179-1''-''179-30'', 30 pp. ISSN~0004-637X. Available from: https://dx.doi.org/10.3847/1538-4357/abd2b6.