GCN Circular 18084
Subject
GRB 150727A: Swift/UVOT Detection
Event
Date
2015-07-28T10:38:48Z (10 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and S. B. Cenko (GSFC) report on behalf of the
Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150727A
86 s after the BAT trigger (Cenko et al., GCN Circ. 18076).
A fading source consistent with the enhanced XRT position (Osborne et
al. GCN Circ. 18079) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 13:35:52.52 = 203.96885 (deg.)
Dec (J2000) = -18:19:31.3 = -18.32536 (deg.)
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).
Preliminary detections in the white, u and uvw2 filters 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 86 236 147 18.28 �� 0.06
white 578 598 20 18.75 �� 0.24
v 4036 4236 197 >18.7
b 554 574 19 >18.5
u 298 548 246 18.75 �� 0.16
m2 4241 4379 136 >19.1
w2 3831 4031 197 19.53 �� 0.36
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening in the direction of the burst.