GCN Circular 23545
Subject
GRB 181213A: Swift/UVOT Observations
Event
Date
2018-12-18T20:20:49Z (7 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 181213A
2352 s after the BAT trigger (Evans et al., GCN Circ. 23525). A fading
optical afterglow consistent with initial reports (Lipunov et al., GCN
Circ. 23526, Hu et al., GCN Circ. 23529) was detected in four of UVOT���s
filters. The lack of detection of this bright burst in the bluer filters
would imply a redshift of z > 1.4, which is not inconsistent with the
spectroscopic redshift of z < 2.4 from Heintz et al. (GCN Circ. 23537).
The preliminary UVOT position is:
RA (J2000) = 16:33:04.86 = 248.27025 (deg.)
Dec (J2000) = +78:29:48.7 = 78.49685 (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 (fc) 2353 2503 294 17.33+/-0.04
white 2633 2653 19 17.15+/-0.10
white 8535 9061 513 19.03+/-0.07
white 66263 67021 738 >21.71
v 2683 2703 19 >17.35
v 26217 37929 1168 >20.45
b 2608 3393 87 17.82+/-0.10
b 8330 15947 230 19.18+/-0.23
b 65351 82801 1115 >20.39
u 2584 3318 216 17.25+/-0.06
u 14999 33141 1327 19.69+/-0.10
u 71983 72421 426 >20.32
uvw1 2559 3113 216 17.50+/-0.11
uvw1 14093 32991 2656 20.07+/-0.16
uvw1 71077 71977 885 >19.97
uvm2 2708 2908 196 >19.26
uvm2 19555 32084 2047 >20.84
uvw2 2659 2679 19 >17.50
uvw2 25310 37634 1771 >20.67
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).