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GCN Circular 2336

XRF030723 (=H2777): Second Epoch Magellan Observations
2003-07-29T19:59:50Z (21 years ago)
Roland Vanderspek at MIT <>
Second Epoch Magellan Observations of XRF030723 (=H2777)

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


We have observed the SXC error circle for the HETE-discovered X-ray
flash XRF030723 (=H2777; Prigozhin et al, GCN 2313) with the MagIC
instrument on the 6.5m Magellan Clay telescope at Las Campanas
Observatory in Chile. Two 200 second, Harris R-band exposures were taken
in an interval centered on July 28.385 UT, at 5.13 days after the
burst.  The seeing was ~0.8 arcsec. Coaddition of the images gives a
limiting magnitude of R = 24.3.

We detect the optical counterpart (Fox et al., GCN 2323) of GRB 030723
at R = 24.2 +/- 0.3.  Combining our photometry with that available from
the GCN Circulars (Bond, GCN 2329; Dullighan et al., GCN 2326; Fox et al.,
GCN 2323), we estimate a late time power law decay index of ~2, and an
early power law decay of 0.9.  The break in the light curve is between
30-50 hours after the burst.  Our measurements have been calibrated
against the USNO photometry data reported by Henden in GCN 2317.

A plot of this light curve can be seen at:

We gratefully acknowledge observational assistance by Matthew J. Holman
and Jeff McClintock.

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