GCN Circular 18192
Subject
GRB 150821A: Swift/UVOT Detection
Event
Date
2015-08-21T19:28:53Z (10 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP) report on behalf
of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150821A
251 s after the BAT trigger (Troja et al., GCN Circ. 18186). We use the
UVOT position as reported there which is consistent with the enhanced
XRT position (Goad et al. GCN Circ. 18191).
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 251 401 147 16.59 +/- 0.03
v 560 580 20 17.21 +/- 0.18
b 484 504 19 17.48 +/- 0.12
u 460 479 19 16.70 +/- 0.11
w1 435 629 39 17.62 +/- 0.18
m2 410 7287 372 >19.8
w2 535 1904 156 19.85 +/- 0.28
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).