GCN Circular 3880
Subject
GRB050824: CORRECTION to UVOT observing times
Date
2005-08-25T19:00:58Z (19 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (MSSL/PSU), R. Fink (GSFC), M. Ivanushkina (PSU), S. Holland
(GSFC/USRA), K. McGowen (MSSL), N. Gehrels (GSFC) on behalf of the Swift
UVOT team
CORRECTION: The mid time and exposure durations previously reported for
observations made by Swift/UVOT of GRB050824 are incorrect (Schady et al.
GCN 3878). The correct times are given below.
The Swift Ultra-Violet/Optical Telescope (UVOT) observations began at
00:53:49 UT, 1.8 hrs after the BAT trigger. UVOT detects a fading source
at a
position consistent with that reported by Gorosabel et al. (GCN 3865) in 5
of its 6 filters. The magnitudes or 3-sigma upper limit in the first
exposure taken in each filter are as follows:
Filter Mid Time (hrs) Exp (s) Mag/3-sig UL
V 1.8 900 20.02+/-0.39
B 5.1 900 20.88+/-0.36
U 3.6 545 19.55+/-0.32
W1 3.4 900 19.85+/-0.33
M2 2.1 532 19.34+/-0.36
W2 7.8 1457 > 20.79
The afterglow has faded below 2-sigma above background 11hrs after the
burst trigger in all filters apart from the V and U, where it is still
detected at the 2.3-sigma and >3-sigma level, respectively.
The magnitudes have not been corrected for extinction. The reddening in
this direction is E_{B-V} = 0.04mag. These magnitudes are based on
preliminary zero-points, measured in orbit, and will require refinement
with further calibration.