Nine tidal disruption event candidates in eROSITA-DE DR1 discovered through supersoft X-ray selection

TL;DR

This paper reports the discovery of nine new tidal disruption event candidates in eROSITA-DE DR1, identified through a novel supersoft X-ray selection method, expanding the known sample and providing insights into their multiwavelength properties.

Contribution

The study introduces a new search technique for supersoft X-ray sources, leading to the identification of five entirely new TDE candidates and analysis of their multiwavelength characteristics.

Findings

Five new X-ray TDE candidates identified.

Two sources have optical counterparts.

Four sources show IR flaring in NEOWISE data.

Abstract

Tidal disruption events are rare and diverse transients that occur when a star is torn apart by a supermassive black hole and accreted, which can result in a supersoft X-ray thermal transient. Here, we present nine tidal disruption event (TDE) candidates identified in eROSITA-DE Data Release 1 through a novel search for such supersoft sources. We select candidates by comparing the catalogued count rates in several combinations of bands and evaluate the nature of selected sources to produce our sample, among which five are entirely new X-ray TDE candidates. All our candidates' X-ray spectra are consistent with soft thermal emission and we show them to have faded through additional Swift observations and catalogued data. We investigate publicly available data from ground- and space-based telescopes and find two of our sources have optical counterparts and four sources show flaring in their NEOWISE IR light curves. The high proportion of our sources with IR flares compared to optically selected TDE samples could suggest a link between supersoft X-ray spectra and IR counterparts. We fit the IR light curves with a model of a spherical dust shell heated by the TDE and find these results to be broadly consistent with those of other TDEs with IR counterparts. Finally, we examine the host galaxies and show them to be similar to the general TDE host population.