RBS 1032: A Tidal Disruption Event in Another Dwarf Galaxy?

TL;DR

This paper confirms that RBS 1032 is a tidal disruption event in a dwarf galaxy, showing significant decay in X-ray luminosity, and discusses implications for tidal disruption rate estimates from archival data.

Contribution

It provides the first confirmation of RBS 1032 as a tidal disruption event in a dwarf galaxy using XMM-Newton data, highlighting potential underestimation of disruption rates in archival surveys.

Findings

RBS 1032 is associated with an inactive dwarf galaxy.

The source's luminosity decayed by a factor of 100-300 since 1990.

Tidal disruption events may be undercounted in archival data.

Abstract

RBS 1032 is a supersoft ($\Gamma\sim5$), luminous ($\sim10^{43}$ erg/s) ROSAT PSPC source which has been associated with an inactive dwarf galaxy at $z=0.026$, SDSS J114726.69+494257.8. We have analyzed an XMM-Newton observation which confirms that RBS 1032 is indeed associated with the dwarf galaxy. Moreover, RBS 1032 has undergone a factor of $\sim100-300$ decay since November 1990. This variability suggests that RBS 1032 may not be a steadily accreting intermediate-mass black hole, but rather an accretion flare from the tidal disruption of a star by the central black hole (which may or may not be intermediate-mass). We suggest that additional tidal disruption events may remain unidentified in archival ROSAT data, such that disruption rate estimates based upon ROSAT All-Sky Survey data may need reconsideration.