{
  "bibcode": "1999GCN...480....1B",
  "body": "GRB 991208 Infrared Detection\n\nJ. S. Bloom, A. Diercks, S. R. Kulkarni, S. G. Djorgovski, N. Z. Scoville,\nD. T. Frayer (Caltech) report on behalf of the Caltech-NRAO-CARA GRB\nCollaboration:\n\n\"On 16 December 1999 UT N. Scoville and D. Frayer observed the field of\nGRB 991208 with the slit-viewing camera of the Near-Infrared Echelle\nSpectrograph (NIRSPEC; McLean et al. SPIE, 1998) at the Keck II 10-m\nTelescope on Mauna Kea, Hawaii. In a stacked 1560-s imaging exposure we\ndetect a K-band source at the position of the transient afterglow (GCN\n#450, GCN #451, GCN #452) of GRB 991208. We find no clear extension of\nthis presumed IR afterglow with respect to other stars in the field.  We\nnote the presence of a faint extended galaxy ~8.3\" W of the source.\nComparison with standard star SJ 9162 (Persson, AJ, 1998) yields a\npreliminary magnitude of the afterglow of K=19.31 +/- 0.15 mag (16.68 Dec\n1999 UT).\n\nExtrapolating the R-band light curve using the reported decay slope from\nMasetti et al. (GCN #462), on 16.68 Dec 1999, we find R - K = 2.7\n(including the small Galactic extinction) implying a spectral index beta =\n-0.77 +/- 0.14 (statistical uncertainty). We note this optical-IR spectral\nindex is inconsistent with reports of an apparent blue spectrum from\npreliminary reductions of optical spectroscopy (GCN #460, GCN #461).\"\n\nA K-band finding chart can be found at \n   http://astro.caltech.edu/~jsb/GRB/grb991208/\n\nThis message may be cited.",
  "circularId": 480,
  "createdOn": 945475787000,
  "email": "jsb@astro.caltech.edu",
  "subject": "GRB 991208 Infrared Detection",
  "submitter": "Josh Bloom at CIT  <jsb@astro.caltech.edu>",
  "eventId": "GRB 991208"
}