AstroNote 2022-99

We report the classification of ZTF20aahmtso/AT2022gri, a UV-bright tidal disruption event (TDE) in a galaxy at z=0.028. 

The nuclear transient was first detected by the Zwicky Transient Facility (ZTF; Bellm et al. 2019; Graham et al. 2019) NSF MSIP Northern Sky Survey on 2022 March 2 with g=19.95 +\- 0.16 mag, and first reported to TNS as a ZTF transient by ZTF_Bot1 on 2022 April 6. The source first passed our filter designed to search for TDE candidates (van Velzen et al. 2019) on 2022 April 14. On 2022 April 22, we obtained an optical spectrum with the Double Spectrograph (DBSP) on the 200-inch Hale telescope, which measured a blue continuum and host galaxy absorption lines at z=0.028. The spectrum has been uploaded to TNS.

Forced photometry obtained with ATLAS and ZTF suggest that the rise time of AT2022gri is ~50 days and the color is persistently blue.  We triggered a Swift observation on 2022 April 29 (around the optical peak), which detected a bright UV source with uvw2 = 16.92 +/- 0.06 mag (host flux subtracted and Galactic extinction corrected). The bright UV flux, with uvw2 - r < -1 mag, persistent blue optical color, and slow rise to peak are consistent with a TDE.

We did not detect any significant X-ray emission with the Swift/XRT, but we are continuing monitoring with Swift.