GRB 191019A: Swift/UVOT Detection

The Swift/UVOT began settled observations of the field of GRB 191019A 3294 s after the BAT trigger (Simpson et al., GCN Circ. 26031). A fading source consistent with the XRT position (Evans et al. GCN Circ. 26034) is detected in the initial UVOT exposures. 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 b 4541 4741 196 19.55+-0.30 uvm2 5361 5561 196 >19.20 u 4336 4536 196 >19.43 v 5156 5356 196 >18.75 uvw1 4131 4331 196 >19.13 uvw2 4952 5151 196 >19.28 white 4746 4946 196 19.66+-0.20 white 27982 28668 668 20.27+-0.18 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998). Additionally, these magnitudes likely include a contribution from the probable host-galaxy, as reported by TSHAO (Reva et al., GCN Circ. 26036), NOT (Fynbo et al., GCN Circ. 26041), and GROND (Guelbenzu et al. GCN Circ. 26042).