GCN Circular 15056
Subject
GRB 130727A: Swift/UVOT Detection
Event
Date
2013-07-28T15:00:47Z (13 years ago)
From
Massimiliano de Pasquale at MSSL-UCL <m.depasquale@ucl.ac.uk>
M. De Pasquale (UCL-MSSL) and M. Stroh (PSU) report on behalf of the
Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 130727A
3495 s after the BAT trigger (Stroh et al., GCN Circ. 15046).
A source consistent with the XRT position (Goad et al. GCN Circ. 15051)
is detected in initial UVOT Finding Chart (FC) exposure taken in white
filter, and it is also detected in summed UVOT exposures taken with white
and u filters. The same source is marginally detected (confidence level
~2 sigma) in b and uw1 filters.
Its UVOT position (J2000) is
RA = 22h 03m 11.62s = 330.79842
Dec = -65d 32m 18.8s = -65.53856.
with an estimated uncertanties of 0.7 arcseconds. The position of the
optical source is consistent with that given by the Faulkes Telescope
(Guidorzi et al., GCN 15050).
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_FC 3495 3645 147 21.27 � 0.34
white 3495 4876 344 21.35 � 0.24
v 3651 16978 880 >20.96
b 4471 4671 197 21.44 � 0.60
u 4266 11215 934 20.99 � 0.26
w1 4061 10452 1082 21.89 � 0.54
m2 3856 5452 355 >20.50
w2 4882 16473 1082 >21.80
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).