{
  "bibcode": "2011GCN.11911....1B",
  "body": "Andreas Brunthaler (MPIfR), Alicia Soderberg (Harvard), Michael Rupen\n(NRAO), Ashley Zauderer, Edo Berger (Harvard), Dale Frail (NRAO), and\nMichael Bietenholz (York U.) report:\n\n\"We observed the variable radio counterpart (GCNs 11836, 11848) of GRB\n110328A / Swift J164449.3+573451 (GCNs 11823, 11824) with the Very Long\nBaseline Array (VLBA) and Effelsberg Radio Telescope for 7 hours beginning\non April 2 at 6:00 UT. Observations at both telescopes were carried out\nat a central frequency of 8.46 GHz.  Based on a preliminary analysis of\nthe VLBA baselines alone, we report a significant detection (SNR=29) of\nthe source at position:\n\nRA:  16 44 49.9313\nDEC: 57 34 59.6895\n\nwith a conservative error estimate of 0.5 mas dominated by the positional\nuncertainty of the phase calibrator, J1638+5720.  This is the most precise\nposition available for the transient.  It is coincident with the measured\npositions for the variable radio, NIR, and X-ray counterparts (GCNs 11836,\n11848, 11853, 11854, 11886) and the host galaxy nucleus (GCN 11881).  The\nsource is not resolved in our VLBA observation; this constrains the size\nto be smaller than that of the beam: 1.9 x 0.7 mas at a position angle of\n18 deg. Further VLBI observations are planned to set limits on the proper\nmotion and source structure.\n\nWe thank the NRAO and Effelsberg scheduling staff for enabling these\nrapid response observations. \"",
  "circularId": 11911,
  "createdOn": 1302291695000,
  "email": "eberger@cfa.harvard.edu",
  "subject": "GRB 110328A / Swift J164449.3+573451: VLBA Observations",
  "submitter": "Edo Berger at Harvard  <eberger@cfa.harvard.edu>",
  "eventId": "GRB 110328A"
}