TITLE: GCN CIRCULAR NUMBER: 24889 SUBJECT: GRB 190627A: Swift/UVOT Detection DATE: 19/06/27 15:57:34 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and E. Sonbas (Adiyaman Univ.) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 190627A 115 s after the BAT trigger (Sonbas et al., GCN Circ. 24888). An uncatalogued source consistent with the BAT position is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 16:19:18.69 = 244.82788 (deg.) Dec (J2000) = -05:17:20.8 = -5.28912 (deg.) with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence). Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 115 144 29 18.15 +/- 0.10 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.18 in the direction of the burst (Schlegel et al. 1998).