GCN Circular 20587
Subject
GRB 170202A: Swift/UVOT Detection
Date
2017-02-03T05:18:40Z (8 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and J. L. Racusin (NASA/GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170202A
84 s after the BAT trigger (Racusin et al., GCN Circ. 20575). A source
consistent with the enhanced XRT position (Osborne et al., GCN 20586)
and is detected in the initial UVOT exposures. No detection in the U and
UV filters is consistent with the reported redshift (de Ugarte Postigo et
al,
GCN Circ. 20584).
The preliminary UVOT position is:
RA (J2000) = 10:10:03.49 = 152.51454 (deg.)
Dec (J2000) = +05:00:41.8 = 5.01161 (deg.)
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).
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 84 233 147 18.31 +/- 0.05
v 625 1419 97 18.27 +/- 0.20
b 551 1345 78 19.18 +/- 0.19
u 295 1837 363 >21.1
w1 675 1812 136 >19.6
w2 1030 1050 19 >19.0
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).