[vsnet-grb-info 2396] GRB051109B: no UVOT source detected

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4233
SUBJECT: GRB051109B: no UVOT source detected
DATE:    05/11/09 18:44:19 GMT
FROM:    Massimiliano de Pasquale at MSSL-UCL  <mdp at mssl.ucl.ac.uk>

M. De Pasquale (UCL-MSSL), G. Tagliaferri (INAF-Brera), A.J. Blustin 
(UCL-MSSL), D. Hinshaw (GSFC-SPSYS), M. Carter (UCL-MSSL),
N. Gehrels (GSFC) on the behalf the UVOT/Swift Team:

  The Swift UVOT began observing the field of GRB051109B at 08:41:03 UT,
84 seconds after the BAT Trigger (Tagliaferri et al, GCN 4222). No new
source with respect to USNO B1.0 is detected within the 4 arcsecond
radius XRT error circle (Campana et al., GCN 4226), either in the first
exposure or in the coadded V-band exposures down to the following 3
sigma magnitude upper limits:

  Filter   T_range (sec)   Exp (sec)   3sigUL
    V         84-284         200       18.9
    V         84-8280        4956      20.8

  The source previously reported in GCN 4222 was actually an artefact
of the onboard processing and was not a real source.

  These values are not corrected for Galactic extinction.