TITLE:   GCN CIRCULAR
NUMBER:  11447
SUBJECT: GRB101204A: Swift/UVOT observations
DATE:    10/12/09 19:11:39 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) & B. Sbarufatti (INAF-OAB/IASFPA) report
on behalf of the Swift-XRT and Swift-UVOT teams

The Swift/UVOT began settled observations of the field of GRB 101204A
126195 s after the BAT trigger (Cummings et al., GCN Circ. 11440).

In agreement with report from Nicuesa Guelbenzu et al., (GCN Circ.  
11445), we
find the afterglow candidate in (Sbarufatti et al. GCN Circ. 11442)
to have faded. Preliminary magnitudes using the UVOT photometric
system (Poole et al. 2008, MNRAS, 383, 627) for summed exposures are:

Filter  T_start(s)  T_stop(s)   Exp(s)       Mag
#####################################################
v       126195       133279     2563    20.51 +/- 0.19
v       271960       336155     3553    > 21.62
u       127505       134378     2329    20.03 +/- 0.12
u       272471       336626     3273    21.27 +/- 0.26
#####################################################

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).