GCN Circular 34582
Subject
Subject: GRB230826A: Swift/UVOT upper limits
Date
2023-08-28T10:21:42Z (8 months ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
Via
email
A. A. Breeveld (UCL-MSSL) and R. A. J. Eyles-Ferris (U Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230826A 114 s after the BAT trigger (Eyles-Ferris et al., GCN Circ. 34565).
No optical afterglow consistent with the enhanced XRT position (Osborne et al., GCN Circ. 34569) 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 114 263 147 >20.0
white 606 5452 312 >20.4
v 657 1105 58 >17.8
b 582 5339 255 >19.6
u 327 5134 481 >19.5
uvw1 707 1320 71 >18.4
uvm2 682 1303 78 >18.4
uvw2 632 1254 78 >18.6
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.243 in the direction of the burst (Schlegel et al. 1998).