TITLE: GCN CIRCULAR NUMBER: 36517 SUBJECT: GRB 240516A: Swift/UVOT Upper Limits DATE: 24/05/20 13:03:20 GMT FROM: Sam Shilling at Lancaster University <shilling.sam@gmail.com> S. P. R. Shilling (Lancaster U.), S. R. Oates (Lancaster U.), N. P. Kuin (UCL-MSSL), A. A. Breeveld (UCL-MSSL) and T. M. Parsotan (GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 240516A 150 s after the BAT trigger (Parsotan et al., GCN Circ. 36493). No optical afterglow consistent with the XRT position (Parsotan et al., GCN Circ. 36493) 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 initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 151 153 2 >17.8 white 150 1689 90 >19.9 v 5228 5427 197 >18.9 m2 5432 5632 197 >18.9 w1 5638 5838 197 >19.1 u 5843 5948 104 >19.1 We note that the first orbit of data only contained observations in the white filter. The other filters are from a later orbit of data. The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 2.390 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/36517. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...