TITLE:   GCN CIRCULAR
NUMBER:  3912
SUBJECT: GRB050904: P60 Observations
DATE:    05/09/04 07:58:41 GMT
FROM:    Derek Fox at PSU  <dfox@astro.psu.edu>

Derek B. Fox (Penn State) and S. Bradley Cenko (Caltech) report on
behalf of a larger collaboration:

"We have imaged the BAT and XRT localization region for GRB050904
(Swift Trigger 153514; Cummings et al., GCN 3910) in a series of
exposures with the Palomar Robotic 60-inch Telescope (P60).  At the
following mean epochs, and to the following limits in R- and i-band,
we identify no new sources within the XRT localization region in our
coadded images:

    Time (UT)    Delta     Limit (mag)
   ===================================
      05:25     +3h33m      R > 20.8
      05:41     +3h49m      i > 19.7
   ===================================

Our photometric calibration is performed against the USNO-B1.0 catalog
R-band and I-band magnitudes for this field for our R- and i-filter
images, respectively.

Our observations of this field are continuing."