GCN Circular 8696
Subject
GRB081222: Swift/UVOT detection of an optical afterglow
Event
Date
2008-12-22T12:52:27Z (17 years ago)
From
Alice Breeveld at MSSL-UCL <aab@mssl.ucl.ac.uk>
A.A. Breeveld (MSSL/UCL) and D. Grupe (PSU) report on behalf of the
Swift UVOT team:
The Swift/UVOT started settled observations of the burst GRB081222
(Grupe et al. GCN Circ. 8691) with the finding chart exposure in
white, 60s after the BAT trigger. The afterglow is detected in the
white and u filters at:
01h 30m 57.59s -34d 05' 41.49" with a 0.5" 90% confidence limit.
This position is consistent with the XRT (Grupe et al. GCN Circ.
8691), REM (Covino et al. GCN Circ. 8692) and GROND (Updike et al. GCN
Circ. 8693) positions. The two white exposures show that the afterglow
is fading with an estimated temporal slope of alpha = 0.85. The
initial UVOT magnitudes are as follows:
Filter Tstart(s) Tstop(s) Exp(s) Magnitude
white 60 210 147.4 14.84+/-0.02
white 873 1023 147.4 17.36+/-0.03
u 272 522 245.8 16.32+/-0.03
The values quoted above are in the UVOT photometric system (Poole et
al. 2008, MNRAS, 383, 627) and are not corrected for the expected
Galactic extinction corresponding to a reddening of E(B-V)=0.021 mag
in the direction of the burst (Schlegel et al. 1998).