[vsnet-grb-info 2398] GRB 051109A: Swift-UVOT Observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4235
SUBJECT: GRB 051109A: Swift-UVOT Observations 
DATE:    05/11/09 19:55:43 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland at milkyway.gsfc.nasa.gov>

GRB 051109A: Swift-UVOT Observations

S. T. Holland (GSFC/USRA), S. Campana (INAF-OAB), P. Smith (UCL/MSSL),
H. Huckle (UCL/MSSL), & N. Gehrels (GSFC) on behalf of
the Swift-UVOT team report:

      The Swift-UVOT began observing the field of GRB 051109A (BAT
Trigger 163136; Palmer, et al. GCN Circular 4213) at
2005-11-09T01:14:09, 109 seconds after the burst.

      We detect an optical transient at

RA(J2000) =  22:01:15.32
Dec(J2000) = +40:49:23.7

with a positional uncertainty of +/-0.5 arcsec (90% confidence),
in agreement with the position of Rykoff, et al. (2005, GCN Circular
4211).  The transient has V = 16.49 +/- 0.07 (1-sigma, statistical)
in an 89 s exposure starting at 2005-11-09T01:14:23, 123 seconds after
the BAT trigger.  This value supercedes the approximate magnitude given
in Palmer, et al. (2005, GCN Circular 4213).  This magnitude has not  
been
corrected for Galactic extinction.

      Further observations and analysis are underway.