TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3384
SUBJECT: GRB 050509b: optical observations
DATE:    05/05/09 06:44:52 GMT
FROM:    Alberto Castro-Tirado at LAEFF-INTA  <ajct@laeff.esa.es>

A. de Ugarte Postigo, A.J. Castro-Tirado (IAA-CSIC Granada),
A. Eigenbrod (EPF de Lausanne), M. Jelinek, J. Gorosabel
and S. Guziy (IAA-CSIC Granada),
                     
report:
                     
"Following the detection by Swift-BAT of the short gamma-ray burst 
GRB 050509b (Hurkett et al. GCN 3381), we have obtained 
two R-band images (300s exposure time each) with the 1.2m Mercator 
telescope at Roque de los Muchachos Observatory in La Palma, 
starting at 04:36:02 UT (i.e. 35.88. min after the onset of 
the burst). The location was observed under poor seeing conditions,
at very high airmass. We do not identify any source within 
the error box provided by Swift-XRT (Kennea et al. GCN 3383) down to 
magnitude 21."

This message may be cited.