{
  "bibcode": "1999GCN...206....1B",
  "body": "GRB 990123 Optical Follow-Up\n\nJ. S. Bloom, R. R. Gal, L. L. Lubin, J. Mulchaey, S. C. Odewahn (CIT), S.\nR. Kulkarni\nreport on behalf of the Caltech-NRAO-CARA GRB Collaboration:\n\n\"We obtained a single B-band image (300-s) at the Palomar 200-inch of the\nfield of GRB 990123 localized by BeppoSAX (GCN #200).  Using images\nobtained of the Landolt standard field 98, we derived a photometric\nzeropoint for the GRB data.  The transient first reported in Odewahn,\nBloom, Kulkarni (GCN #202) is well-detected at B = 18.93 +/- 0.03 mag (Jan\n23.578 UT).  The uncertainty includes the systematic and statistical\nuncertainties though no color term was applied.  For reference, we find\nthe following B = 19.59 +/- 0.04 for the object at position ra:\n15:25:32.7, dec: +44:44:29.7 (J2000).\n\nAbsolute astrometry was obtained by comparison of 34 objects near the\noptical transient with the USNO-A2.0 Catalogue.  The r.m.s. uncertainties\nof the astrometry are 0.28 arcsec (ra) and 0.26 arcsec (dec).  We find the\nposition of the optical transient to be, ra: 15:25:30.34, dec: +44:45:59.1\n(J2000).  Based on the POSS-II F-Plate of this field, the purported host\ngalaxy (see GCN #202) appears offset from the OT by 1.8 arcsec (+/- 0.4\narcsec) to the South.  Further analysis is underway.\n\nThis message may be cited.\"",
  "circularId": 206,
  "createdOn": 917136111000,
  "email": "jsb@astro.caltech.edu",
  "subject": "GRB 990123 Optical Follow-up",
  "submitter": "Josh Bloom at CIT  <jsb@astro.caltech.edu>",
  "eventId": "GRB 990123"
}