TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3992
SUBJECT: GRB 050915B: Swift/UVOT Upper Limits
DATE:    05/09/16 20:19:47 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland@milkyway.gsfc.nasa.gov>

GRB 050915B: Swift/UVOT Upper Limits

S. T. Holland (GSFC/USRA), A. Falcone (PSU), M. Carter (UCL/MSSL),
P. Smith (UCL/MSSL), and N. Gehrels (GSFC) report on behalf of the
Swift/UVOT team:

      The Swift/UVOT began observing the field of GRB 050915B 121
seconds after the BAT trigger (Falcone et al. GCN 3987). No new source
is detected at the position of the XRT error circle (Falcone et
al. GCN 3989) in the initial 100 second V-band image down to a 5-sigma
upper limit of 17.5, or in summed exposures with any of the filters
down to the following 5-sigma magnitude upper limits:

Filter  T_range (s)     Exp (s)  5sig UL

V       133 - 25,406     1824     19.2
B       279 - 35,461     2983     20.4
U       265 - 31,288     2381     20.2
UVW1    251 - 30,503     2972     21.0
UVM2    237 - 29,595     3006     20.7
UVW2    294 - 35,995     2609     20.8

The magnitudes are uncorrected for extinction.