GCN Circular 8287
Subject
Swift trigger 325707: Swift/UVOT Upper Limits
Date
2008-09-24T12:53:00Z (16 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (MSSL-UCL) and S. Immler (CRESST/GSFC/UMD) report on behalf of
the Swift/UVOT team:
The Swift/UVOT observed the field of the GRB candidate, BAT trigger number
325707 (Immler et al., GCN Circ. 8285), with settled exposures starting
78s after the trigger. We do not find any new source in the UVOT
observations inside the BAT error circle (Immler et al., GCN Circ. 8285)
or anywhere in the UVOT field of view. We note that the field is very
crowded, and no observations were made in the white band filter due to the
presence of a bright star in the field of view.
The 5-sigma upper limits in the UVOT photometric system (Poole et al.
2008, MNRAS, 383, 627) for detecting a source in the first v finding chart
exposure and subsequent co-added exposures from the first orbit of
observations are:
Filter T_start T_stop Exp Mag (5-sigma UL)
(s) (s) (s)
================================================
v (fc) 78 478 393.4 > 18.4
v 599 759 40.1 > 18.4
b 558 848 28.8 > 17.6
u 533 833 58.5 > 17.9
uvw1 509 808 58.4 > 17.5
uvm2 484 783 58.4 > 17.3
uvw2 574 734 58.4 > 17.7
The values quoted above are not corrected for the expected Galactic
extinction corresponding to a reddening of E(B-V) = 0.39 mag in the
direction of the burst (Schlegel et al. 1998).