{
  "bibcode": "2005GCN..4214....1S",
  "body": "B. E. Schaefer (Louisiana State), E.S. Rykoff (U Mich), W. Rujopakarn (U \nMich), F. Yuan (U Mich), R. Quimby (U Texas), K. Alatalo (Berkeley), T.A. \nMcKay (U Mich), C. Akerlof (U Mich), report on behalf of the ROTSE \ncollaboration:\n\nA fast fading optical transient has been discovered inside the error\ncircle for GRB 051109A (Swift trigger 163136) by the ROTSE-IIIb telescope,\nlocated at McDonald Observatory (cf. Rykoff et al. GCN 4211). The source\nfaded as a power law. At the central time of UT 01:16:05 (228 seconds\nafter the Swift trigger), the magnitude was 16.21. (Magnitudes are\nunfiltered and calibrated against R-band magnitudes for nearby comparison\nstars.) The source is continuing to fade, but accurate magnitudes will\nhave to await a more detailed analysis due to nearby faint stars.\n\nWith these magnitudes, the power law index for the decline is -0.4. If \nthis decline continues unbroken, then at a time around two hours after the \nburst (UT 03:12), the magnitude should be 17.7. Eight hours after the \nburst (UT 09:12), a magnitude of 18.3 might be expected.",
  "circularId": 4214,
  "createdOn": 1131503884000,
  "email": "schaefer@grb.phys.lsu.edu",
  "subject": "GRB 051109A: ROTSE-III Decline rate for Optical Counterpart",
  "submitter": "Brad Schaefer at LSU  <schaefer@grb.phys.lsu.edu>",
  "eventId": "GRB 051109A"
}