TITLE: GCN CIRCULAR NUMBER: 19333 SUBJECT: GRB 160422A: Swift/UVOT Candidate Afterglow DATE: 16/04/23 00:48:34 GMT FROM: Frank Marshall at GSFC F. E. Marshall (NASA/GSFC) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160422A 32624 s after the LAT trigger (Yassine et al. GCN Circ. 19329). A candidate optical afterglow is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 02:48:22.79 = 42.09497 (deg.) Dec (J2000) = -57:52:30.4 = -57.87511 (deg.) with an estimated uncertainty of 0.45 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 33427 34064 627 19.71 +/- 0.07 u 32624 33420 783 19.05 +/- 0.11 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). [GCN OPS NOTE(25apr16), Per author's request, the LAT reference was corrected.]