[vsnet-grb-info 6601] GRB 080905B: Watcher optical detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8207
SUBJECT: GRB 080905B: Watcher optical detection
DATE:    08/09/10 12:26:32 GMT
FROM:    John French at UCD,Ireland  <jfrench at bermuda.ucd.ie>

John French (UCD School of Physics, DARK/NBI), Gary Melady (UCD School of Physics), Daniele Malesani, Paul Vreeswijk (DARK/NBI) report on behalf of
a larger collaboration:

The Watcher 40 cm robotic telescope at Boyden Observatory, South Africa, began imaging the field of GRB 080905B (Stroh et al al. GCN 8182) at
16:56:28 UT, 43 s after the Swift triggger. In a stacked sequence of 10 unfiltered 10 s exposures, with a mid-time of 16:57:37 UT (112 s after the
Swift trigger), we detect a point source inside the refined XRT error circle (Osborne et al. GCN 8189), at a position consistent with the
detections reported by Holland et al. (GCN 8192) , Vreeswijk et al. (GCN 8191) and Stroh et al. (GCN 8182).

We measure a magnitude of 16.2 +/- 0.2 for the source, based on comparison with the USNO-B1 star at RA 20:06:51.361, Dec -62:32:52.55. Further
analysis is ongoing.