GCN Circular 21411
Subject
GRB 170803A: Swift/UVOT Detection
Event
Date
2017-08-04T13:04:24Z (8 years ago)
From
Sam Emery at MSSL-UCL <samuel.emery.15@ucl.ac.uk>
S.W.K. Emery (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 170803A
88 s after the BAT trigger (LaPorte et al., GCN Circ. 21405).
GRB 170803A was also triggered by Fermi GBM
(Veres and Meegan GCN Circ. 21406)
A fading source consistent with the XRT position
(Beardmore et al., GCN Circ. 21407)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 11:39:44.11 = 174.93380 (deg.)
Dec (J2000) = -16:18:38.0 = -16.31055 (deg.)
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).
Preliminary 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 88 238 147 18.10 +/- 0.06
white 580 2241 322 19.69 +/- 0.12
u_FC 300 550 246 18.58 +/- 0.16
u 775 2366 175 >19.34
b 556 2386 191 20.02 +/- 0.35
uvw1 6216 23821 982 >20.74
uvm2 17025 17715 679 >20.57
uvw2 5602 30135 990 >21.05
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).