GCN Circular 21207
Subject
GRB 170604A: Swift/UVOT Observations
Date
2017-06-05T19:10:10Z (7 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170604A
128 s after the BAT trigger (Page et al., GCN Circ. 21191).
We detect a fading afterglow consistent with the position given by XRT
(Page et al., GCN Circ 21196) and ground-based optical detections
(Izzy et al., GCN Circ 21197; Schady, GCN Circ. 21200; Mazaeva et al.,
GCN Circ 21203).
The preliminary UVOT position is:
RA (J2000) = 22:50:37.52 = 342.65632 (deg.)
Dec (J2000) = -15:24:43.9 = -15.41220 (deg.)
with an estimated uncertainty of 0.1 arc sec. (radius, 90% confidence).
Preliminary magnitudes and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (fc) 128 278 147 15.81+-0.03
white 3968 5603 393 18.72+-0.06
white 39053 39959 885 20.57+-0.18
v 4378 6013 393 18.94+-0.31
v 34480 44756 1268 >19.89
b 3763 5398 393 19.26+-0.15
b 38141 39048 885 >20.86
u (fc) 287 429 279 15.70+-0.03
u 4993 5193 196 18.51+-0.16
u 28543 29132 576 >19.72
uvw1 4788 4988 196 18.47+-0.19
uvw1 23318 46354 1633 20.20+-0.27
uvm2 4583 6169 344 18.58+-0.18
uvm2 44762 45661 885 >20.37
uvw2 4174 5809 393 19.53+-0.26
uvw2 32392 40613 1700 >20.86
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).