{
  "editedBy": "Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Tyler Barna at University of Minnesota <tylerpbarna@gmail.com>",
  "eventId": "GRB 971214",
  "version": 2,
  "submitter": "Shri Kulkarni at Caltech <srk@astro.caltech.edu>",
  "format": "text/plain",
  "subject": "GRB971214: Keck R & I-band Observations",
  "editedOn": 1720570361777,
  "circularId": 27,
  "createdOn": 884476800000,
  "bibcode": "1998GCN....27....1K",
  "body": "#027\nS. R. Kulkarni, A. N. Ramaprakash, J. Bloom, S. Djorgovski, Caltech;\nR. Goodrich, Keck Observatory/CARA and D. Frail, VLA/NRAO\nreport on behalf of the Caltech GRB effort:\n\n\"The optical transient (IAUC 6788) of GRB 971214 (IAUC 6787; IAUC 6792)\nwas observed by J. Aycock using the LRIS instrument on Keck II.  The\nobservations were conducted between 1400--1600 UT of January 10, 1998\nand images were obtained in the R band.  The seeing was consistently\n0.86 arcsec and 12 frames each of five minute duration were obtained.\nA source is clearly detected at the position of the OT.  This source is\nfainter by 5.5 +/- 0.17 mag compared to object 2 of Henden et al. (GCN\nnote [#016] of Dec 24, 1997).  We measured pixel offsets between this source\nand object 2 and compared to similar offsets in the LRIS I-band image\nof Dec 15.47 1997 UT (see GCN note of Dec 17, 1997).  The offsets\nmatch to better than 0.15 arcsec in each axis.\n\nA power law fit to the I-band data of Halpern et al. (IAUC 6788) and\nour LRIS I-band data of Dec 16.52 and Dec 17.45 UT predict an I-band\nmagnitude between 26.2 and 27.0 on January 10, 1998.  The uncertainty\nrepresents maximum errors in the extrapolation.  Diercks et al. (IAUC\n6791) note that the OT had R-I=1.0+/-0.4 on Dec 15.5 1997 UT.  The\nsubsequent two R band measurements (IAUC 6791) appear to track the\nI-band points (to within errors).  Thus, if there is no color evolution\nin the OT then the predicted R band magnitude on 10 January 1998 UT is\nbetween 27.2 and 28.0 mag with an offset uncertainty of 0.4 mag.  We\nconclude that either the OT has stopped its power law decay or more\nlikely the host of the OT has an R magnitude of 25.6 mag.\"\n\nThis is citable information.",
  "email": "circulars@gcn.nasa.gov"
}