AstroNote 2021-83

We report the UV and X-ray detection of optical tidal disruption event (TDE) ZTF20acyydkh/AT2021ack. The transient was first reported to TNS as ATLAS21blz on 2021 Jan 12 but was first detected in the Zwicky Transient Facility (ZTF) MSIP Northern Sky Survey on 2020 Dec 20. Our Swift follow-up observations on 2021 Mar 03 measure a bright UV flux of uvw2=19.3 mag with estimated coincident optical flux observed with ZTF of g > 19.8 mag. Swift XRT observations from 2021 Mar 03 detect 7 soft photons with a count rate of ~0.005 cts/s corresponding to a flux of 4e-13 ergs/s/cm^2 and luminosity of 2e43 ergs/s for a luminosity distance of 625 Mpc. We are continuing to monitor the TDE with Swift to determine the X-ray evolution of the source, and will report if it gets bright enough for timing and detailed spectral X-ray observations.