Optical and X-ray Observations of the Afterglow to XRF030723
  The X-ray-flash XRF030723 was detected by the HETE satellite and rapidly disseminated, allowing for an optical transient to be detected ~1 day after the burst. We discuss observations in the optical with Magellan, which confirmed the fade of the optical transient. In a 2-epoch ToO observation with Chandra, we discovered a fading X-ray source spatially coincident with the optical transient. We present spectral fits to the X-ray data. We also discuss the possibility that the source underwent a rebrightening in the X-rays, as was observed in the optical. We find that the significance of a possible rebrightening is very low (~1 sigma). 
N. Butler, A. Dullighan, P. Ford, G. Ricker, R. Vanderspek, K. Hurley,   J. Jernigan, D. Lamb, and C. Graziani