{
  "bibcode": "2000GCN...514....1T",
  "body": "G. B. Taylor and D. A. Frail (NRAO) report on behalf of a larger\ncollaboration:\n\n\"Following the detection of the radio afterglow on Dec 18.16 (Taylor &\nBerger, GCN 483) from the bright BATSE burst GRB 991216 (Kippen et\nal., GCN 463) we observed with the Very Long Baseline Array (VLBA) for\n2 hours beginning on December 18.32 UT.  The flux density measured at\n8.4 GHz was 705 +/- 85 microJy.  The source is unresolved by these\nobservations with a size less than 1 mas (size < 6.6 pc given the\nprobable redshift of 1.02 reported by Vreeswijk et al. in GCN 496).\nThe VLBA position is at ra = 05h09m31.2983s dec = +11d17'07.262\"\n(equinox J2000) with a conservative error of 0.001 arcsec in each\ncoordinate.  This position is within 0.02 arcsec of the radio position\nderived by Taylor & Berger (GCN 483) who claim an uncertainty of 0.1\narcsec, but is 0.321 arcsec from the optical afterglow position\nreported by Dolan et al. (GCN 486) who claim an uncertainty of 0.15\narcsec.  Given that the optical and radio afterglow should be\ncoincident, we suggest that the optical astrometric position given by\nDolan et al. suffers from a systematic error.\"\n\nThis message may be cited.",
  "circularId": 514,
  "createdOn": 946924780000,
  "email": "gtaylor@aoc.nrao.edu",
  "subject": "GRB 991216 VLBA Observations",
  "submitter": "Greg Taylor at NRAO  <gtaylor@aoc.nrao.edu>",
  "eventId": "GRB 991216"
}