Application of The Wind-Driven Model to A Sample of Tidal Disruption Events

Kohki Uno; Keiichi Maeda

doi:10.3847/2041-8213/abca32

paper

Application of The Wind-Driven Model to A Sample of Tidal Disruption Events

arXiv:2009.03852 · doi:10.3847/2041-8213/abca32

Abstract

An origin of the Optical/UV radiation from tidal disruption events (TDEs) has recently been discussed for different scenarios, but observational support is generally missing. In this Letter, we test applicability of the `Wind-Driven model' (Uno & Maeda 2020) to a sample of UV/Optical TDEs. With the model, we aim to derive the physical properties of the Optical/UV TDEs, such as mass-loss rates and characteristic radii. The model assumes optically thick continuous outflows like stellar winds, and one key question is how the wind-launched radius is connected to physical processes in TDEs. As one possibility, through a comparison between the escape velocities estimated from their black-hole masses and the wind velocities estimated from observed line widths, we propose that the outflow is launched from the self-interaction radius ( $R_{SI}$ ) where the stellar debris stretched by the tidal force intersects; we show that the escape velocities at $R_{SI}$ are roughly consistent with the wind velocities. By applying the model to a sample of Optical/UV TDE candidates, we find that explosive mass ejections ( $≳ 10 M_{⊙} y r^{- 1}$ ) from $R_{SI}$ ( $\sim 1 0^{14} cm$ ) can explain the observed properties of TDEs around peak luminosity. We also apply the same framework to a peculiar transient, AT2018cow. The model suggests that AT2018cow is likely a TDE induced by an intermediate-mass black hole ( $M_{BH} \sim 1 0^{4} M_{⊙}$ ).

arXiv comment8 pages, 1 table, 4 figures, accepted for publication in the ApJL

Application of The Wind-Driven Model to A Sample of Tidal Disruption Events

Abstract

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