GCN Circular 18546
Subject
GRB 151031A: Swift/UVOT Detection
Event
Date
2015-10-31T22:42:11Z (10 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and E. Sonbas (Adiyaman Univ.) report on
behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 151031A
439 s after the BAT trigger (Sonbas et al., GCN Circ. 18538). A source
at the VLT position (Malesani et al, GCN Circ. 18540) and consistent with
the XRT position (Evans et al. GCN Circ. 18541) is detected in the initial
UVOT exposures.
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 439 1020 314 20.63 +/- 0.16
v 595 8257 627 >20.1
b 695 7642 588 >20.2
u 670 7437 430 20.34 +/- 0.28
w1 645 8677 635 >20.0
m2 620 8462 627 >20.0
w2 746 8053 607 >21.0
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).