TITLE: GCN CIRCULAR NUMBER: 40011 SUBJECT: GRB 250329B: Swift/UVOT Upper Limit DATE: 25/04/02 15:39:59 GMT FROM: Mike Siegel at PSU/Swift MOC mhs18@psu.edu
M.H. Siegel (PSU) and R. Caputo (GSFC) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 250329B 7.4 ks after the SVOM trigger sb25032902 (Xie et al., GCN Circ. 39925). We do not detect an afterglow at the position of the XRT counterpart (Beardmore et al., GCN Circ. 39939).
Preliminary detections and 3-sigma upper limits for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag(AB) u 7392 8531 1121 >21.00 u 92986 110466 2225 >20.80
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).
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