[vsnet-grb-info 6819] Swift UVOT observations of GRB081025

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8414
SUBJECT: Swift UVOT observations of GRB081025
DATE:    08/10/26 17:50:10 GMT
FROM:    Patricia Schady at MSSL/Swift  <msslba at yahoo.co.uk>

P. Schady (MSSL/UCL) and J. Mao (INAF-OAB) report on behalf of the Swift UVOT team.

The Swift UltraViolet/Optical Telescope (UVOT) began ToO observations
of the Swift-BATSS GRB 081025 (Copete et al., GCN Circ. 8409), 20.7 hours
after the trigger. We do not detect any new source at the XRT position
reported in GCN Circ. 8411 (Mao et al.) in any of the individual or
co-added images down to the following 3-sigma upper limits:

Filter  Tstart(hrs)  Exp(s)  3-sigma UL
b        21.2        130     > 19.44
u        20.9        885     > 20.18
uvw1     20.7        1015    > 20.60
uvm2     22.2        886     > 20.63

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 extinction corresponding to a reddening of E(B-V)=0.02 mag
in the direction of the burst (Schlegel et al. 1998).