TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1885
SUBJECT: GRB 030226, optical observations
DATE:    03/02/26 19:17:15 GMT
FROM:    Peter Garnavich at U of Notre Dame  <pgarnavi@miranda.phys.nd.edu>

 P. Garnavich (Notre Dame), K. von Braun (DTM), K. Stanek (CfA)

We have calibrated the R-band images of the GRB 030226 field
(Fox et al. GCN 1879; von Braun et al. GCN 1881) taken
with the 1-m Swope telescope on Feb. 26 (UT). The Landolt
standard field PG1323-086 (Landolt 1992, AJ, 104, 340) was
observed at the end of the photometric night. We estimate the
following magnitudes for stars near the optical afterglow:

Star A  11:33:03.214  +25:51:30.73 (2000)  R=15.39 +/-0.05
Star B  11:32:59.808  +25:52:38.73 (2000)  R=17.06 +/-0.05

where most of the error is due to the uncertain airmass correction.
Star A was noted in GCN 1881 as having a USNO magnitude of 15.0.

Using this calibration we find the following brightness for
the afterglow from the Swope data:

Feb. 26.305 (3.5 hours after the burst)  R=18.44 +/-0.05

The images show only a 0.02 mag variation in the
brightness of the afterglow over a 20 minutes span.

A finder chart for the afterglow and calibrated stars
can be found at: http://www.nd.edu/~pgarnavi/grb030226.jpg

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