TITLE:   GCN CIRCULAR
NUMBER:  3986
SUBJECT: GRB050915: Swift/UVOT upper limits
DATE:    05/09/15 20:42:37 GMT
FROM:    Alexander Blustin at MSSL-UCL  <ajb@mssl.ucl.ac.uk>

A. J. Blustin (UCL-MSSL), D. Grupe (PSU), T. Poole (UCL-MSSL),
P. Roming (PSU), N. White (GSFC), D. Hinshaw (GSFC-SPSYS),
N. Gehrels (GSFC) report on behalf of the Swift-UVOT team:

The Swift/UVOT began observing the field of GRB050915 85 s
after the BAT trigger (Grupe et al. GCN 3977). No new source is
detected at the position of the refined XRT error circle (Grupe
et al. GCN 3983) in the initial 100 s V-band image down to a
3-sigma upper limit of 19.0, or in summed exposures with any of
the filters down to the following 3-sigma magnitude upper limits:

Filter T_range (s) Exp (s) 3sig UL

V      85-6154     1049    20.3
B      230-17031   324     20.6
U      216-12846   958     20.9
W1     203-11939   958     20.5
M2     188-6743    640     20.2
W2     246-677     59      19.6

The magnitudes are uncorrected for extinction.