TITLE:   GCN CIRCULAR
NUMBER:  45819
SUBJECT: GRB 261005B: Swift/UVOT Upper Limits
DATE:    26/10/06 13:43:34 GMT
FROM:    Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL), N. Klingler (NASA-GSFC/UMBC/CRESST II) and T.M. Parsotan (GSFC) report on behalf of the Swift/UVOT team:

The Swift/UVOT started observing the field of GRB 261005B 4424 s after the BAT trigger (Parsotan et al., GCN Circ. 45812).
No optical afterglow consistent with the enhanced XRT position (Page et al., GCN Circ. 45815) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the data available are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white             5451         5651          197         >20.4
b                 5247         5446          197         >19.8
u                 5040         5239          197         >19.3
v                 4424         4624          197         >18.3
uvw1              4835         5035          197         >18.7
uvw2              5658         5836          175         >19.1
uvm2              4629         4829          197         >18.1


The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.12 in the direction of the burst (Schlegel et al. 1998).