GCN Circular 3698
Subject
GRB050726: Swift UVOT observations
Event
Date
2005-07-29T15:26:48Z (21 years ago)
From
Tracey Poole at MSSL <tsp@mssl.ucl.ac.uk>
T. Poole (MSSL), A. Moretti (OAB), S. T. Holland (GSFC), M. Chester
(PSU), L. Angelini (GSFC-JHU), N. Gehrels (GSFC) on behalf of the Swift
UVOT team
The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of
GRB050726 (Barthlemy et al. GCN 3682) on 26th July 2005 at 05:02:07 UT.
We confirm the detection of a source inside the BAT and XRT error circle
(Barthlemy et al. GCN 3682, A. Moretti et al. GCN 3683) in the V band
only. The source is detected in the initial V band observation, then
drops below the 3 sigma detection threshold. It is not detected in
the U, B or the UV filters.
The aperture used for all observations was 6 arcsec. The limiting
magnitudes are given to a 3 sigma limit.
V filter
start exposure mid magnitude
time time time
after after
burst burst
(s) (s) (s)
123 100 173 17.35+/-0.09 - source detection
298 10 303 17.47 - limiting magnitude
382 10 387 17.43 - limiting magnitude
466 10 471 17.36 - limiting magnitude
551 10 556 17.29 - limiting magnitude
635 10 640 17.49 - limiting magnitude
720 10 725 17.40 - limiting magnitude
9825 900 10275 19.76 - limiting magnitude
21647 900 22097 19.83 - limiting magnitude
Other filters - limiting magnitudes
Filter start exposure mid limiting
time time time magnitude
after after
burst burst
(s) (s) (s)
b 269 59 485 19.38
b 4992 1800 6189 21.31
b 29659 12 29665 18.72
u 255 59 216 19.23
u 4124 2700 16888 21.06
uvw1 241 59 457 19.29
uvw1 4020 100 4070 19.49
uvw1 11639 2003 17763 21.44
uvm2 352 68 196 19.41
uvm2 10731 1800 19738 21.48
uvw2 284 89 500 19.88
uvw2 5939 1300 13820 21.62
The magnitudes are based on preliminary zero points, measured in orbit,
and will require refinement with further calibration.
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