{
  "bibcode": "1998GCN...176....1E",
  "body": "GRB 981220: Optical Observations\n\nA. C. Eichelberger, J. S. Bloom, S. R. Kulkarni, R. R. Gal (Caltech),\nE. G. Martin (UCB), and D. A. Frail (NRAO) report:\n\nOn December 23, 1998 (UT) we obtained four 300-s R-band imaging of the\nfield of GRB 981220 with LRIS on the Keck II 10-m telescope. Based on\nastrometry from the USNO-A2 catalogue, at the position of the transient\nradio source (RT; GCN #170) we find a faint source in the stacked\nimage. Our astrometry is good to 0.3 arcsec (rms) in each coordinate.\nLacking observations of standard stars, we have used the standard\nR-band zeropoint of LRIS.  Using a 1.2 arcsec aperture we find the\nobject at the position of the RT to have R= 26.7 +/- 0.7 mag on 23.4\nDec 1998 UT. For reference, this zeropoint implies that the USNO star\nat ra: 03:42:28.32, dec:  +17:09:42.60 (J2000) has a magnitude of\nR=18.35.\n\nAlthough the object appears somewhat extended in our 0.8 arcsec (FWHM)\nseeing, deeper imaging is required to firmly establish that this object\nis indeed the host galaxy of the GRB.\n\nThis message is citeable.",
  "circularId": 176,
  "createdOn": 914905593000,
  "email": "srk@astro.caltech.edu",
  "subject": "GRB 981220:Optical Observations",
  "submitter": "Shri Kulkarni at Caltech  <srk@astro.caltech.edu>",
  "eventId": "GRB 981220"
}