GCN Circular 5861
Subject
GRB 061126: Swift/UVOT Observations
Date
2006-11-26T19:28:23Z (17 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (MSSL/UCL) and B. Sbarufatti (INAF-IASFPA) report on behalf of the
Swift/UVOT team:
The Swift/UVOT began observing the field of GRB 061121 at 09:14:41 on
2006-11-26, 27.6 minutes after the BAT trigger (Sbarufatti et al., GCN 5854).
An optical counterpart is detected in the V, B, U, UVW1 and UVM2 filters, as
well as in the White-band filter (160-650 nm) at a position consistent with
that reported by Vanden Berk et al. (GCN 5856). We can, therefore, put a
photometric upper limit on the redshift of GRB 061126 of z < ~1.5.
The photometry results for each UVOT filter are given below where Tmid is
the average time of the exposure, in seconds, since the BAT trigger. For those
filters in which the afterglow is detected we report the magnitude of the
afterglow in the first and last exposures taken before the spacecraft slewed to
another target 4.3hrs after the BAT trigger. The upper limit (3 sigma) reported
for the UVW2 filter is taken from a co-added exposure and for all detections
that are less than 3-sigma above background, the significance of the detection
is given. The quoted errors do not include the 0.1 mag systematic uncertainty
in the photometric zero points.
Filter Tmid Exposure Mag Err
(s) (s)
==========================================
V 3423 197 19.29 0.58 (1.9 sigma)
9178 295 19.86 0.78 (1.4 sigma)
B 2809 197 19.75 0.24
7097 197 21.04 0.75 (1.5 sigma)
U 7702 197 19.54 0.27
15331 110 > 18.72
UVW1 5664 279 19.34 0.37
14515 886 > 20.04
UVM2 3627 197 19.79 0.56
13608 886 21.38 0.85 (1.3 sigma)
UVW2 5767 393 > 20.00
White 1655 98 18.50 0.12
8111 197 19.72 0.22
==========================================
The values quoted above are not corrected for the expected Galactic
extinction of E_{B-V} = 0.18 mag (Schlegel et al. 1998).