{
  "bibcode": "2005GCN..3332....1P",
  "body": "Jason X. Prochaska (UCO/Lick Obs.), Sara Ellison (U. Victoria), \nR. J. Foley (UCB), J. S. Bloom (UCB), & H.-W. Chen (MIT) report on behalf \nof the GRAASP collaboration:\n\n\"We observed the afterglow of GRB 050502a for 3600s with HIRES on the KeckI     \ntelescope starting at UT 05:53:46 on May 02, 2005, 3.5 hours after the initial  \nburst.  We obtained a low SNR, high resolution spectrum (R~40000).  We report  \na tentative redshift of z=3.793 based on the following lines of evidence:\n \n1.  We detect a prominent flux discontinuity at 4400 Ang, blueward of which no  \nflux is present.  We interpret the flux decrement at 4400 A as the Lyman \nlimit absorption produced by the host of the GRB. \n \n2.  The flux blueward of ~5870 Ang is 'patchy', i.e. indicative of the Lya \nforest.  A broad absorption feature is present at 5820 Ang, which we \ninterpret as the Lya absorption due to the ISM of the host galaxy.\n \n3.  We identify a strong absorption feature at 6040 Ang, which is consistent\nwith SiII1260 at z=3.793.\n\nFurther analysis is underway.\n \nThis message can be cited.\"",
  "circularId": 3332,
  "createdOn": 1115037452000,
  "email": "hchen@space.mit.edu",
  "subject": "GRB 050502A: Redshift measurement based on Keck HIRES Observations",
  "submitter": "Hsiao-Wen Chen at MIT/CSR  <hchen@space.mit.edu>",
  "eventId": "GRB 050502A"
}