GCN Circular 22454
Subject
GRB 180224A: Swift/UVOT Detection
Event
Date
2018-02-26T17:54:14Z (8 years ago)
From
Sam LaPorte at PSU <sjl5346@psu.edu>
GRB 180224A: Swift/UVOT Detection
S. J. LaPorte (PSU) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180224A
85 s after the BAT trigger (Lien et al., GCN Circ. 22442).
A fading source consistent with the XRT position
(Evans et al. GCN Circ. 22443) also detected by (Lipunov et al. GCN Circ.
22444; Watson et al. GCN Circ. 22446; Pozanenko et al. GCN Circ. 22448)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 13:30:44.10 = 202.68377 (deg.)
Dec (J2000) = +38:04:44.5 = 38.07902 (deg.)
with an estimated uncertainty of 0.46 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 61 211 294 18.9 +/- 0.07
white 553 5337 287 20.7 +/- 0.33
v 603 1397 97 >18.4
b 552 1348 78 >19.5
u 273 5063 500 >20.3
w1 652 1446 97 >18.7
m2 824 844 19 >18.2
w2 751 771 19 >17.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).