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GCN Circular 7844

Subject
GRB 080605: Swift-UVOT refined analysis
Date
2008-06-06T20:45:57Z (16 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).
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