{
  "bibcode": "2002GCN..1572....1W",
  "body": "W. M. Wood-Vasey, G. Aldering, and B. C. Lee, Lawrence Berkeley\nNational Laboratory, using images obtained by E. F. Helin, S. Pravdo,\nM. Hicks, and K. Lawrence (Near-Earth Asteroid Tracking project, Jet\nPropulsion Laboratory), report upper limits for pre-discovery\nobservations at the location of the object identified by Fox et\nal. (GCN 1564) as the optical counterpart to GRB 20021004 from\nunfiltered observations with the Oschin 48\" telescope at Palomar\nObservatory (the same instrument as used by Fox et al.).\n\nA co-addition of historical images from 13 October 2001, 26 October\n2001, 5 November 2001, 3 September 2002, 3 October 2002 (all dates UT)\nfrom the same instrument show no source visible at this location to a\nlimiting unfiltered magnitude of 22.3 (calibrated to USNO R-band stars\non the image frame) at a S/N of 3.\n\nA coaddition of images from 3 October 2002 UT shows no source visible\nat this location to a limiting unfiltered magnitude of 21.4\n(calibrated to USNO R-band stars on the image frame) at a S/N of 3.\n\nThe specific UT times for the 3 October 2002 UT observations are:\n\n07:24:18\n07:54:50\n08:25:19\n\nThe historical co-additions of the all \nimages mentioned above is available at:\n\nhttp://supernova.lbl.gov/~wwoodvas/GRB/",
  "circularId": 1572,
  "createdOn": 1033776756000,
  "email": "bclee@lbl.gov",
  "subject": "GRB021004: Upper limits from recent and historical observations",
  "submitter": "Brian Lee at LBL  <bclee@lbl.gov>",
  "eventId": "GRB 021004"
}