{
  "bibcode": "2010GCN.11138....1L",
  "body": "A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), C. Copperwheat (U. Warwick)\nreport for a larger collaboration:\n\nWe observed the field of GRB 100823A (Mangano et al. GCN 11135) using the\nWilliam Herschel Telescope on La Palma with the ACAM instrument. Observations\nwere conducted in the z-band, and began at 00:37 UT, approximately 7.2 hours\nafter the burst.\n\nWithin the refined X-ray error circle (Goad et al. GCN 11136)  we identify a\nsource, at\n\nA:\nRA(J2000): 01:22:48.97\nDEC(J2000) 05:50:08.1\n\nHowever, we note that a source is also present in the DSS2 images of the field\nat this position.\n\nAdditionally we note the presence of a brighter source, not present in the DSS\nimages at\n\nB:\nRA(J2000): 01:22:48.79\nDEC(J2000) 05:50:10.9\n\nThis source may be the afterglow of GRB 100823A (offset approximately ~6 arcseconds\nfrom the XRT position),  or alternatively could either be a red source, not visible in the\nDSS2 red image, or a source with high proper motion.\n\nFurther observations will be required to assess the nature of any variability.\n\nImages can be found at\n\nhttp://www.star.le.ac.uk/~anl/100823A",
  "circularId": 11138,
  "createdOn": 1282624104000,
  "email": "A.J.Levan@warwick.ac.uk",
  "subject": "GRB 100823A: WHT observations",
  "submitter": "Andrew Levan at U.of Leicester  <A.J.Levan@warwick.ac.uk>",
  "eventId": "GRB 100823A"
}