TITLE:   GCN CIRCULAR
NUMBER:  10274
SUBJECT: GRB091208A: Swift/UVOT refined analysis
DATE:    09/12/09 13:43:27 GMT
FROM:    Massimiliano de Pasquale at MSSL-UCL  <mdp@mssl.ucl.ac.uk>

  M. De Pasquale (MSSL/UCL) and E. Hoversten (PSU) report on the behalf of 
the Swift team:

Swift/UVOT observed the field of GRB091208A from 4.32 ks to 4.33 ks after 
the BAT trigger in the v filter and then from 26.01 to 26.71 ks after the 
trigger in u, v and white filters. No new source is detected in the BAT 
error circle  (Barthelmy et al., GCN Circ. 10264). We caution though that 
a small fraction of BAT error circle is not covered by UVOT exposures.
3 sigma upper limits on magnitudes are as follows:

Filter T_start(s)  T_stop(s)      Exp(s)     Mag
v          4318       4328           10     >17.4
v         26513      26717          200     >19.4
wh        26261      26507          243     >21.1
u         26008      26255          243     >20.1

The values quoted above are on the UVOT Photometric System
(Poole et al., 2008, MNRAS 383,627). They are not corrected for
the expected strong Galactic extinction, corresponding to a reddening
of E(B-V)=1.6.