ATCA radio detection of the TDE AT2022dsb
ATel #15293; Adelle Goodwin (ICRAR-Curtin), Gemma Anderson (ICRAR-Curtin), James Miller-Jones (ICRAR-Curtin), Zhu Liu (MPE), Adam Malayi (MPE), and Arne Rau (MPE)
on 24 Mar 2022; 06:14 UT
Credential Certification: Adelle Goodwin (adelle.goodwin@curtin.edu.au)
Subjects: Radio, Transient, Tidal Disruption Event
We report radio observations of the tidal disruption event (TDE) AT2022dsb taken with the Australia Telescope Compact Array (ATCA). AT2022dsb was first reported as a new optical transient ASASSN-22cs on 2022 March 1 (TNS Astronomical Transient Report No. 138375) associated with the galaxy ESO 583- G 004, and later classified as a TDE at a redshift of z=0.023 by ePESSTO+ (TNS Astronomical Transient Report No. 12024). Liu et al. reported the detection of a soft X-ray transient by SRG/eROSITA on 2022 February 17 coincident with the optical position of the source (ATel #15259), as well as an optical spectrum taken with the FLOYDS spectrograph mounted at the LCOGT 2m telescope at Haleakala Observatory on 2022 February 26 that showed broad H alpha and He II emission lines. These X-ray and optical spectral properties further confirmed the TDE nature of the transient.
We observed the optical position of the source on 2022 March 21 UT 21:30 with ATCA at 4cm (central frequencies of 5.5 and 9.0 GHz) using 2 GHz of bandwidth at each central frequency, in the 64 MHz mode. We reduced the data using standard procedures in the Common Astronomy Software Application, including flux calibration with PKS 1934-638 and phase calibration with PKS 1514-241. We detected a point source in both observing bands at J2000 RA 15:42:21.7, Dec -22:40:14.3 with a positional uncertainty of 0.35 arcseconds along the major axis with a position angle of 58 degrees; coincident with the location of the host galaxy. We measure a flux density of 593+/-19 microJy at 5.5 GHz and 536+/-17 microJy at 9 GHz. Further radio observations have been requested to constrain the spectral shape of this transient. We encourage additional multi-wavelength follow up of this interesting source.
We thank the ATCA Observatory staff for enabling these triggered observations. We acknowledge the Gomeroi people as the traditional owners of the ATCA Observatory site.
