TITLE: GCN CIRCULAR NUMBER: 26988 SUBJECT: GRB200120A: SRG/eROSITA discovery of X-ray afterglow DATE: 20/02/05 15:50:25 GMT FROM: Arne Rau at MPE P. Weber (FAU), A. Rau (MPE), Th. Dauser (FAU), I. Kreykenbohm (FAU), J. Wilms (FAU) report: The location of the Fermi/GBM long duration GRB 200120A (#26831, #26840, #26851, #26856, #26857, #26974) was observed by SRG/eROSITA as part of its all-sky survey between UTC 2020 Jan 16th and Jan 24th.  Throughout this period, the instrument scanned over the position with a cadence of 4hr. On UTC Jan 20th 23:18:15 (820 seconds after the Fermi/GBM trigger) we detected a bright and quickly fading X-ray source localized to RA(J2000) =   09:08:32.1 (137.13364 deg) Dec(J2000) = -70:25:11   (-70.43628 deg) with an uncertainty of ~4" arcsec radius. This position is consistent with the Fermi/GBM (#26831) and IPN (#26856) localizations, suggesting the source to be the X-ray afterglow of GRB200120A. At the time of discovery, the source was detected with a count rate of 44+/-2 cnt/s in the 0.2-10keV band, corresponding to a flux of approx. 1x10E-10 erg/cm^2/s. The source was also found during the next scan 4hr later. By then, it had faded to 2.8+/-0.5 cnt/s (approx. 6x10E-12 erg/cm^2/s). Further detections were obtained in the following three scans with count rates of ~1+/-0.3 cnt/s. Nothing was seen in the scans prior to the Fermi/GBM detection.