{
  "bibcode": "2002GCN..1593....1H",
  "body": "J. P. Halpern, N. Mirabal, E. K. Armstrong, C. C. Espaillat (Columbia),\nJ. Kemp (Joint Astronomy Centre and Columbia) report for the MDM GRB\nfollow-up team:\n\n\"Continued monitoring of the optical afterglow of GRB 021004 with\nthe MDM 1.3m yields the following measurements on On 2002 Oct 6 UT:\n\n\t\t--------------------\n\t\t  UT      R     +/-\n\t\t--------------------\n\t\t02:41\t19.84\t0.03\n\t\t07:03\t19.91\t0.02\n\t\t11:39\t20.00\t0.02\n\t\t--------------------\n\nHere we used the revised calibration of Henden (GCN #1583) in which\nthe reference has star has R=15.52.  Previous R magnitudes reported\nin GCN #1578 would have to be decreased by 0.12 to match this reference.\nThe mean R-band decay between 8 and 48 hours as determined by the NOT and\nMDM measurements can be described as a power law of slope -1.05, but with\nhighly significant deviations from a power law (Winn et al., GCN #1576)\nthat are robust against cross-calibration issues.\"\n\nAn updated decay curve will be maintained at:\n\nhttp://www.astro.columbia.edu/~jules/021004.ps",
  "circularId": 1593,
  "createdOn": 1033938674000,
  "email": "jules@astro.columbia.edu",
  "subject": "GRB 021004: Optical Decay",
  "submitter": "Jules Halpern at Columbia U.  <jules@astro.columbia.edu>",
  "eventId": "GRB 021004"
}