GCN Circular 20894
Subject
GRB 170317A: Swift/UVOT Detection
Date
2017-03-17T17:00:57Z (8 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and S. J. LaPorte (PSU) report on behalf of
the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB
170317A 87 s after the BAT trigger (LaPorte et al., GCN Circ.20885).
A fading source consistent with the XRT position (Beardmore et al.
GCN Circ. 20887) is detected in the initial UVOT exposures. The GRB
afterglow was also observed by Mazaeva et al. (GCN Circ. 20886) and
Mao et al. (GCN. Circ. 20889) in the R band.
The preliminary UVOT position is:
RA (J2000) = 06:12:14.82 = 93.06173 (deg.)
Dec (J2000) = +50:29:35.2 = 50.49310 (deg.)
with an estimated uncertainty of 0.43 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 87 237 147 17.53 +/- 0.04
v 629 1597 117 18.36 +/- 0.19
b 554 1349 78 19.12 +/- 0.19
u 299 549 246 17.75 +/- 0.07
w1 678 7320 588 20.20 +/- 0.29
m2 653 7115 398 >19.8
w2 604 8141 607 >20.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.19 in the direction of the burst
(Schlegel et al. 1998).