GCN Circular 26024
M. H. Siegel and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 191016A 45 ks after the BAT trigger (Gropp et al., GCN Circ. 26008). A source is detected consistent with the XRT position and the optical source reported by Watson et al. (GCN Circ. 26010, 26015), Zheng and Filippenko (GCN Circ. 26011), Hu et al. (GCN Circ. 26017), Kim et al. (GCN Circ. 26018) and Toma et al. (GCN Circ. 26019). The preliminary UVOT position is: RA (J2000) = 02:01:04.68 = 30.26948 (deg.) Dec (J2000) = +24:30:35.7 = 24.50990 (deg.) with an estimated uncertainty of 0.5 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limit 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 45023 46878 1822 21.09+/-0.17 white 50812 52638 1794 21.21+/-0.19 white 56420 56938 506 >21.23 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.09 in the direction of the burst (Schlegel et al. 1998).