GCN Circular 15045
Subject
GRB 130725B: Swift/UVOT Observations
Date
2013-07-26T17:50:43Z (11 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
S. R. Oates (UCL-MSSL) and C. A. Swenson (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 130725B
72 s after the BAT trigger (Swenson et al. GCN Circ. 15029;
Swenson GCN Circ. 15044).
A source consistent with the enhanced XRT position (Sbarufatti and Swenson GCN Circ. 15040)
is detected in the initial UVOT exposures in all filters except for uvm2 and uvw2.
The non-detection in these filters suggests a redshift ~<2.
The preliminary UVOT position is:
RA (J2000) = 14:16:57.76 = 214.24068 (deg.)
Dec (J2000) = -11:07:41.8 = -11.12827 (deg.)
with an estimated uncertainty of 0.50 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 72 221 147 16.67 +/- 0.03
v 614 6315 252 19.16 +/- 0.27
b 540 559 19 18.20 +/- 0.28
u 284 534 246 17.35 +/- 0.06
w1 663 6725 236 20.01 +/- 0.36
m2 6320 16621 1003 >21.1
w2 4265 4465 197 >20.1
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.061 in the direction of the burst
(Schlegel et al. 1998).