{
  "bibcode": "2002GCN..1579....1E",
  "body": "Mike Eracleous (Penn State), Bradley E. Schaefer (U. Texas), Jeff Mader\n(McDonald Obs.), and Craig Wheeler (U. Texas) report on behalf of the\nHobby-Eberly Telescope GRB followup team:\n\n\"We have obtained spectra of the optical counterpart of GRB021004 (GCN\n1564) with the 9.2-m Hobby-Eberly telescope.  The observations\nconsisted of a series of three 15-minute exposures starting at\n2002-Oct-5 3:34UT and a series of three 15-minute exposures starting\nat 2002-Oct-5 8:24UT with the Marcario Low-Resolution Spectrograph.\nThe spectra cover the range 4200 - 9200 Angstrom at a spectral\nresolution of approximately 15 Angstrom.  We detect the Mg II\nabsorption lines reported by Fox et al.  (GCN 1569) and confirm the\npresence of two absorption systems at z=1.38 and z=1.60.  We do not\ndetect any significant absorption corresponding to the Mg I line at a\nrest wavelength of 2853 Angstrom (with z=1.60) as reported by Fox et\nal.  (GCN 1569).  We do not find any lines suggestive of absorption\nsystems at higher redshifts.  We also detect the Fe II UV1, UV2, and\nUV3 absorption multiplets associated with both redshift systems (the\nFe II lines associated with the z=1.60 have already been reported by\nFox et al.).  In addition we also find four prominent absorption lines\nat observed wavelengths of 4633, 4664, 5109, and 5152 Angstrom, which\nwe have not yet been able to identify.  The ratio of wavelengths\nbetween these pair of lines approximately equals (1+1.38)/(1+1.60),\nwhich suggests that these lines are from the same features with rest\nwavelengths of 1947 and 1960 Angstroms.  The continuum shape can be\ndescribed by a power law of the form f_nu ~ nu^{-p}.  After correcting\nfor Galactic extinction we tentatively estimate a power-law index of \np ~ 1.5.\"\n\nThis message may be cited.",
  "circularId": 1579,
  "createdOn": 1033828440000,
  "email": "mce@astro.psu.edu",
  "subject": "GRB021004: Optical Spectroscopy",
  "submitter": "Mike Eracleous at PSU, Astro.Dept.  <mce@astro.psu.edu>",
  "eventId": "GRB 021004"
}