TITLE: GCN CIRCULAR NUMBER: 17375 SUBJECT: GRB 150201A: Swift/UVOT Upper Limits DATE: 15/02/02 19:29:53 GMT FROM: Frank Marshall at GSFC F. E. Marshall (NASA/GSFC) and J. K. Cannizzo (CRESST/GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150201A 93 s after the BAT trigger (Cannizzo et al., GCN Circ. 17368). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 17369) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 93 243 147 >21.0 u_FC 306 556 246 >20.4 white 93 913 239 >21.5 v 635 829 39 >18.6 b 561 755 35 >19.8 u 306 729 265 >20.3 w1 685 705 19 >19.6 w2 784 804 19 >19.6 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).