TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2326
SUBJECT: Magellan Observations of XRF030723 (=H2777)
DATE:    03/07/26 15:28:55 GMT
FROM:    George Ricker at MIT  <grr@space.mit.edu>

Magellan Observations of XRF030723 (=H2777)

A. Dullighan, N. Butler, R. Vanderspek, J. Villasenor,  and G. Ricker (MIT)

write:

We have observed the SXC error circle for the HETE-discovered X-ray 
flash XRF030723(=H2777; Prigozhin et al, GCN 2313) with the LDSS2 
instrument on the 6.5m Magellan Clay telescope at Las Campanas 
Observatory in Chile. Four 6 minute Harris R-band exposures were 
taken in an interval centered on July 24.31 UT, extending from 24.8 h 
to 25.2 hours after the burst.  The seeing was ~0.6 arcsec. 
Coaddition of the images gives a limiting magnitude of R = 24.5 
magnitudes.

We detect the suggested optical counterpart (Fox et al., GCN 2323) of 
GRB 030723 at R = 21.13 +/- 0.05 magnitudes.  Combining our 
photometry with that of Fox et al, we estimate a power law decay 
index of 1.6. Our measurements have been calibrated against the 
recent USNO photometry data reported by Henden in GCN 2317.

We gratefully acknowledge observational assistance by A. McWilliam and D. Osip.

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