{
  "bibcode": "2002GCN..1620....1D",
  "body": "S. G. Djorgovski, A. Barth, P. Price, D. Fox, W.L.W. Sargent, R. Simcoe,\nA. Soderberg, S. Yost, E. Berger, S.R. Kulkarni, F.A. Harrison (Caltech) and\nD. Frail (NRAO) report on behalf of the Caltech-NRAO-CARA GRB collaboration:\n\nAnalysis of spectra of the OT + host galaxy associated with GRB 021004,\nobtained by W. Sargent and R. Simcoe using the LRIS spectrograph at the\nWMKO Keck-1 telescope, confirms the exitence of the multi-component z ~ 2.3\nredshift systems reported by Chornock & Filippenko (GCN 1605), Salamanca\net al. (GCN 1611) and Mirabal et al. (GCN 1618).\n\nFor the emission component of the Ly-alpha line we measure the flux of\n1.7e-16 cgs, which after the correction for the Galactic extinction becomes\n2.2e-16 cgs.\n\nThis places the host galaxy of GRB 021004 in the top 0.5 to 1 percent of the\nfield galaxy population at comparable redshifts, in terms of the Ly-alpha\nline flux (on the basis of data by A. Shapley, C. Steidel, et al., priv.\ncomm.)\n\nIn the currently popular cosmology with h = 0.65, Omega_0 = 0.3, and\nLambda_0 = 0.7, the luminosity distance is 6.2e28 cm, and the inferred\nLy-alpha luminosity is 1.1e+43 erg/s.  Using the standard conversion, this\ncorresponds to an unobscured star formation rate of 15 M_sun/yr.  However,\nthis is certainly a lower limit, since the blue half of the Ly-alpha line is\nabsorbed, there is an unknown atennuation factor due to the resonant\nscattering and absorption, and an unknown, fully obscured star formation\ncomponent.  Thus, the true SFR in the host is at least twice as high, and\ncould be an order of magnitude higher (or more).\n\nThis note can be cited.",
  "circularId": 1620,
  "createdOn": 1034314015000,
  "email": "george@astro.caltech.edu",
  "subject": "GRB 021004:  Host Galaxy Star Formation Rate",
  "submitter": "George Djorgovski at Caltech/Palomar  <george@astro.caltech.edu>",
  "eventId": "GRB 021004"
}