GCN Circular 13725
Subject
GRB 120907A: Swift/UVOT Detection
Date
2012-09-07T19:17:57Z (13 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (MSSL-UCL) and J. L. Racusin (NASA/GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120907A
142 s after the BAT trigger (Racusin et al., GCN Circ. 13716).
A source consistent with the enhanced XRT position (Goad et al. GCN Circ. 13722)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 04:59:00.00 = 74.75002 (deg.)
Dec (J2000) = -09:18:54.0 = -9.31501 (deg.)
with an estimated uncertainty of 0.52 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
v 449 6811 471 >19.5
b 398 567 39 19.02 +/- 0.29
u 142 392 246 17.67 +/- 0.08
w1 498 666 40 18.27 +/- 0.32
m2 473 1122 79 18.68 +/- 0.36
w2 424 642 39 18.56 +/- 0.37
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).