SRG/eROSITA detection of X-ray emission from TDE candidate AT 2021blz
ATel #14407; Zhu Liu, Arne Rau, Adam Malyali, Andrea Merloni, Iullia Grotova (all MPE)
on 19 Feb 2021; 10:47 UT
Credential Certification: Arne Rau (arau@mpe.mpg.de)
Subjects: X-ray, Transient, Tidal Disruption Event
During the third consecutive all-sky survey (eRASS3), the eROSITA instrument (Predehl et al. arXiv:2010.03477) on board the SRG observatory detected X-ray emission from the location of the TDE candidate AT 2021blz. AT 2021blz was recently reported by the ATLAS team (TNS Astronomical Transient Report No. 98076) on 2021-01-31. Optical spectroscopic classification was performed on 2021-02-04 by ePESSTO+.
In eRASS3, the source position was observed between 2021-02-10 and 2021-02-12, with a total exposure time of ~194s. Based on a total of 5 source photons and assuming a spectral shape of an unabsorbed black body with kT=80 eV, we derive a 0.2-2.3keV flux of ~5.7E-14 erg/s/cm^2 (2.0-12.E-14, 90% confidence level). This result indicates that the X-ray emission is very faint at the time of SRG/eROSITA observations, i.e. L(0.2-2.3keV) ~ 2.8E41 erg/s (1.0-5.8E41 erg/s), assuming a redshift of 0.045.
The position of AT 2021blz was also observed in the preceding two all-sky surveys in February and August 2020 with a total exposure time of ~202s and 267s, respectively. No source was detected with a combined 3-sigma upper limit of 4.4E-14 erg/s/cm^2 in 0.2-2.3keV band.
