{
  "bibcode": "1999GCN...201....1O",
  "body": "GRB 990123: Bright New Source, Possible Optical Transient\n\nS. C. Odewahn, J. S. Bloom, and S. R. Kulkarni (CIT) report on behalf of\nthe Caltech-NRAO-CARA GRB Collaboration:\n\n\"We imaged the BeppoSAX localization (Piro et al. 1999; GCN #199) of GRB\n990123 with a CCD camera on the Palomar 60-inch. In each 400-s R-band\nimage a source clearly brighter than on DSS was seen at position: RA,DEC =\n15:25:30.53, +44:46:00.5 (J2000) (preliminary astrometry).  This\nlocalization is well-within the BeppoSAX error radius.  Though DSS and\nR-band are somewhat different bandpasses, given the apparent brightness\nof the source relative to the DSS image, we suggest that this source is\nthe optical transient of GRB 990123.\n\nA faint source at the limit of detectability is seen on the POSS-II\nimage at this location and we suggest this may is the host galaxy of\nthe GRB.  If true, we have discovered the brightest host galaxy of any\nGRB known thus far --- this would be commensurate with the expectation,\nbased on the high GRB flux as measured by BeppoSAX, that this burst is\nnearer than any localized previously.\n\nPreliminary photometry based on the APM catalogue puts the optical\ntransient at R = 18.2 (Jan 23.565 UT) and the host galaxy at R ~= 21.3.\nMore precise photometric and astrometric calibrations are currently under\nway.\n\nThe discovery image may be obtained at the following web page:\n    http://astro.caltech.edu/~jsb/GRB/grb990123.html\n\nFollow-up of this most bright burst is urged at all wavelengths.\n\n\nThis message may be cited.\"",
  "circularId": 201,
  "createdOn": 917111898000,
  "email": "jsb@astro.caltech.edu",
  "subject": "GRB 990123: Bright New Source, Possible Optical Transient",
  "submitter": "Josh Bloom at CIT  <jsb@astro.caltech.edu>",
  "eventId": "GRB 990123"
}