TITLE: GCN CIRCULAR NUMBER: 31627 SUBJECT: ZTF22aaajecb/AT2022cmc: Submillimeter Array detection DATE: 22/02/22 00:10:41 GMT FROM: Daniel Perley at Liverpool JMU D. A. Perley (LJMU), A. Y. Q. Ho (UC Berkeley), G. Petitpas, and G. Keating (SMA) report: We observed the location of the fast optical (Andreoni et al., GCN 31590), radio (Perley et al., GCN 31592), and X-ray (Pasham et al., GCN 31601) transient ZTF22aaajecb/AT2022cmc with the Submillimeter Array (SMA) at 1.3 mm (230 GHz) and 850 microns (340 GHz). Observations were carried out between 09:58-16:33 UT on 2022-02-18 and between 08:54-16:11 UT on 2022-02-20. Only a subset of the array was available due to ongoing maintenance work. We detect a strong source at the location of the transient during both epochs in both frequency channels. Preliminary calibration gives a flux density estimate of 12 mJy at 230 GHz on 2022-02-18. Given the VLT redshift of z=1.193 (Tanvir et al., GCN 31602) this makes this object one of the most luminous submillimeter transients identified to date, comparable only to the most luminous GRB afterglows and to the relativistic TDE Swift J1644+57. We thank the SMA staff for executing this observation during the maintenance period. DisclaimerNone