GCN Circular 27944
F. E. Marshall (NASA/GSFC) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 200613A 43621 s after the FERMI/LAT trigger (Ohno et al., GCN Circ. 27931). A source consistent with the XRT position (Kennea et al., GCN Circ. 27936) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 10:12:10.03 = 153.04178 (deg.) Dec (J2000) = +45:45:14.1 = 45.75391 (deg.) with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence). This position is consistent with the optical counterparts reported by Kann et al. (GCN Circ. 27935 & 27938) and Pozanenko (GCN Circ. 27937). Preliminary detections and 3-sigma upper limits 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 44416 45204 775 19.65 +/- 0.07 v 45211 45427 213 >18.6 u 43621 44409 775 19.02 +/- 0.12 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).