AstroNote 2023-326

We report the classification of the optical transient ZTF23abaujuy/AT2023rvb (RA = 19:21:12.55, Dec = -22:38:39.60, z = 0.0815) as a tidal disruption event (TDE) due to its persistent blue optical colors, bright UV flux measured by the Neil Gehrels Swift telescope, and follow-up optical spectroscopy.

ZTF23abaujuy/AT2023rvb was first reported to TNS by the Zwicky Transient Facility (ZTF) on 2023 Sep 08. A single r-band detection was made by ZTF on 2019 Sep 05 and a single g-band detection was made on 2021 Aug 03, however the source was not further detected until 2023 Aug 16 with an r-band detection of r = 20.87 +/- 0.34 mag. The source rose to peak over the next ~29 days to a peak color of g-r = -0.32 +/- 0.15 mag.

We triggered a follow-up observation with the DeVeny optical spectrograph on the Lowell Discovery Telescope (LDT) and a spectrum was taken on 2023 Oct 15. This follow-up spectrum displayed broad H-alpha emission and probable broad He II emission, with host galaxy absorption lines implying a redshift of z = 0.0815.

Our Swift follow-up observations on 2023 Oct 26 measure a bright UV flux (host-subtracted) of uvw2 = 19.9 +/- 0.14 mag, uvm2 = 19.93 +/- 0.19 mag, uvw1 = 19.95 +/- 0.25 mag, consistent with the decay of the optical light curve. We detect no X-ray source in the XRT image.

On 2023 Nov 17, another follow-up spectrum was obtained with the Low Resolution Imaging Spectrometer (LRIS) on Keck-I, which showed a steep, blue continuum, broad H-alpha emission, and broad He II emission.

Based on the blue optical colors, follow-up optical spectroscopy, and UV detections, we classify ZTF23abaujuy as a TDE.