GCN Circular 28342
Subject
GRB 200901A: Swift/UVOT Detection
Event
Date
2020-09-01T20:16:07Z (6 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and K. K. Simpson (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200901A 3053 s after the BAT trigger
(Simpson et al., GCN Circ. 28335).
A possible optical afterglow consistent with the XRT position (Kennea et al., GCN Circ. 28341) is
detected in the initial UVOT exposures in the white filter only. It is not clear whether the source
is fading.
Preliminary detections and 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 3053 3202 147 20.6 +/- 0.3
white 3916 4115 197 20.5 +/- 0.2
v 4326 4526 197 >19.1
b 3711 3910 197 >20.4
u 3211 4987 290 >20.0
w1 4736 4936 197 >19.1
m2 4531 4731 197 >19.1
w2 4121 4321 197 >19.3
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of
E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).