TITLE: GCN CIRCULAR NUMBER: 39765 SUBJECT: GRB250312A: Swift/UVOT Upper Limits DATE: 25/03/17 20:21:01 GMT FROM: Mike Siegel at PSU/Swift MOC mhs18@psu.edu
M. H.Siegel (PSU) and A. Melandri (INAF-OAR) on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 250312A 464s after the BAT trigger (Melandri et al., GCN Circ. 39686). No optical afterglow consistent with the enhanced XRT position (Evans et al., GCN Circ. 39693) 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) 464 1563 165 >20.47 white 743 1563 223 >20.50 b 718 1539 38 >18.84 b 6529 33943 1081 >20.52 u 6324 23538 403 >19.80 uvw1 21814 22713 885 >19.99 uvm2 10515 16904 1012 >19.85 uvw2 6939 28312 1082 >20.24
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.015 in the direction of the burst (Schlegel et al. 1998).
View this GCN Circular online at https://gcn.nasa.gov/circulars/39765. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...