GCN Circular 33595
Subject
GRB 230409B: Swift/UVOT Detection
Event
Date
2023-04-09T14:26:27Z (3 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
GRB 230409B: Swift/UVOT Detection
N. Paul Kuin (UCL/MSSL) and A. P. Beardmore (U. Leicester) report
on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of
GRB 230409B 386 s after the BAT trigger (Beardmore et al.,
GCN Circ. 33592). A weak fading source consistent with the
XRT position (Beardmore et al. GCN Circ. 33592) is detected
in the initial UVOT exposures at position RA=329.5158,
Dec=52.8321 deg.
Preliminary detections and 3-sigma upper limits using the
UVOT photometric system (Breeveld et al. 2011, AIP Conf.
Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 386 536 147 19.35 +/- 0.20
v 542 1931 156 >18.1
b 642 2029 156 >19.4
u 616 2004 156 >19.0
w1 592 1980 156 >18.8
m2 567 1955 156 >19.2
w2 692 1906 136 >20.0
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.226 in the direction of the burst
(Schlegel et al. 1998).