GCN Circular 7844
Subject
GRB 080605: Swift-UVOT refined analysis
Date
2008-06-06T20:45:57Z (17 years ago)
From
Paul Kuin at MSSL <npkuin@googlemail.com>
N. P. M. Kuin (MSSL/UCL), B. Sbarufatti (INAF-IASFPA), F. Marshall (GSFC),
and P.Schady (MSSL/UCL), report on behalf of the Swift UVOT team
The Swift UltraViolet/Optical Telescope (UVOT) began observations
of GRB 080605, on June 5, 2008, at 23:49:19 UT, 82 seconds after
the initial Swift BAT trigger (Mangano et al., GCN Circ. 7794), and
started the finding chart exposure in the white filter at 102
seconds after the trigger.
The refined uvot position of GRB080605 is RA=262.12522, Dec=+4.01555
deg.(= 17:28:30.05 +04:00:55.97), with an accuracy of 0.5", consistent
with the positions reported in GCN Circ. 7830 (Holland et al.) and
7835 (Goad et al.).
The GRB is found close (about 4" distant) to a star, which may cause
an error in the measured flux, especially at later times. For this
analysis we use a small 2" aperture which which reduces the
contamination, and apply a standard aperture correction. We note that
the DSS image indicates the presence of a weak, possibly extended
source near the position of the afterglow.
The magnitudes with 1-sigma errors for GRB080605 are given below
for the initial observation sequence.
Filter Tstart(s) Tstop(s) Exp(s) Magnitude
wh 102 201 98.2 18.11 +/- 0.06
v 208 607 393.5 18.53 +/- 0.11
wh 858 957 98.2 20.02 +/- 0.17
uvm2 615 788 38.9 >18.38 (3 sigma UL)
uvw1 639 813 38.9 >18.95 (3 sigma UL)
uvw2 720 739 19.5 >18.16 (3 sigma UL)
b 27679 28264 571.7 21.10 +/- 0.27
u 18432 41856 550.7 21.17 +/- 0.43
The values quoted above are on the UVOT Photometric System
(Poole et al, 2008, MNRAS 383,627). They are not corrected for the
expected galactic reddening of E(B-V) = 0.137 in the direction of
the burst (Schlegel et al. 1998).