{
  "bibcode": "2000GCN...661....1B",
  "body": "The redshift of GRB 000418\n\nJ. S. Bloom, A. Diercks, S. G. Djorgovski, D. Kaplan, and S. R. Kulkarni\n(Caltech) report on behalf of the larger Caltech-NRAO-CARA GRB\ncollaboration:\n\n\"We observed the transient position of GRB 000418 (Klose et al. GCN #645)\nwith the Echellette Spectrograph and Imager (ESI) on the Keck II 10-m\nTelescope on Mauna Kea at 2.318 May 2000 UT.  In a 1200-s exposure we\ndetect both broadband continuum and a strong doublet in emission at\nwavelengths Lambda = 7894.0,7899.4 Angstrom (preliminary reduction).  \nFurther observations of the source are in progress.\n\nWe attribute this doublet to [OII] emission from the underlying host\ngalaxy.  If so, this would place GRB 000418 at a redshift of \nz=1.11854 +/- 0.0007, placing it near the median of GRB redshifts thus far\nobtained. Assuming a flat lambda cosmology of H_0 = 65 km/s/Mpc, Omega_m =\n0.3, Omega_lam = 0.7 the luminosity distance to the GRB is \nD_L = 2.515 x 10^28 cm.  Since the total fluence of the burst is \n1.3 x 10^{-5} erg cm^{-2} (Hurley et al. GCN #642), we estimate the total\nisotropic energy release of the GRB to be E = 4.9 x 10^52 erg.\"\n\nThis message may be cited.",
  "circularId": 661,
  "createdOn": 957335131000,
  "email": "jsb@astro.caltech.edu",
  "subject": "The redshift of GRB 000418",
  "submitter": "Josh Bloom at CIT  <jsb@astro.caltech.edu>",
  "eventId": "GRB 000418"
}