GCN Circular 12735
Subject
GRB 111225A: Swift/UVOT Observations
Date
2011-12-27T16:51:36Z (13 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 111225A
95 s after the BAT trigger (Siegel et al., GCN Circ. 12720).
A source consistent with the XRT position is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 00:52:37.22 = 13.15510 (deg.)
Dec (J2000) = +51:34:19.5 = 51.57208 (deg.)
with an estimated uncertainty of 0.67 arc sec. (radius, 90% confidence).
The afterglow has not been detected since the first orbit. 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
u (fc) 95 345 246 19.46 +/- 0.17
v 610 18443 2140 >21.1
u 4385 16744 1475 >20.66
uvw1 659 12668 1212 >20.4
uvm2 634 11879 1337 >20.5
uvw2 354 17652 1780 21.36 +/- 0.31
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.26 in the direction of the burst
(Schlegel et al. 1998).