A central TDE candidate detected through spectroscopic continuum emission properties in a SDSS blue quasar

TL;DR

This study identifies a potential tidal disruption event (TDE) candidate in a SDSS blue quasar by analyzing spectroscopic continuum emissions and long-term light curves, providing strong evidence for a central TDE.

Contribution

The paper introduces a novel method combining spectroscopic continuum analysis and long-term light curve modeling to detect TDE candidates in quasars, specifically identifying SDSS J2308 as a likely TDE.

Findings

SDSS quasars and optical TDEs occupy distinct regions in $T_{BB}$-$R_{BB}$ space.

SDSS J2308's properties are consistent with TDE models.

High confidence levels (>5σ) support the TDE interpretation for SDSS J2308.

Abstract

In this manuscript, properties of spectroscopic continuum emissions are considered to detect potential tidal disruption event (TDE) candidates among SDSS quasars. After considering the simple blackbody photosphere model applied to describe quasar continuum emissions with parameters of blackbody temperature $T_{BB}$ and blackbody radius $R_{BB}$, SDSS quasars and reported optical TDEs occupy distinct regions in the space of $T_{BB}$ and $R_{BB}$. Then, through the dependence of $R_{BB}$ on $T_{BB}$ for SDSS quasars, 402 outliers in SDSS Stripe82 region can be collected. Among the 402 outliers, the SDSS J2308 at $z=1.16$ is mainly considered, due to its SDSS spectrum observed around the peak brightness of the light curves. With the 7.2-year-long light curves described by theoretical TDE model, the determined $T_{BB}$ and $R_{BB}$ through its spectroscopic continuum emissions are consistent with the TDE model determined values, to support the central TDE. Moreover, considering simulated results on continuum emissions of SDSS quasars around $z\sim1.16$, confidence level higher than 4$\sigma$ can be confirmed that the continuum emissions of SDSS J2308 are not related to normal quasars. Furthermore, accepted CAR process to simulate intrinsic AGN variability, the confidence level higher than $3\sigma$ can be confirmed that the long-term light curves of SDSS J2308 are related to a central TDE. Jointed the probabilities through both spectroscopic and photometric simulations, the confidence level higher than $5\sigma$ can be confirmed to support the central TDE in SDSS J2308.