{
  "bibcode": "2005GCN..3709....1C",
  "body": "Hsiao-Wen Chen (MIT), Ian Thompson (Carnegie Observatory), Jason X. \nProchaska (UCO/Lick Observatory), Josh Bloom (UCB) report on behalf of the \nGRAASP collaboration:\n\n\"We observed the afterglow of GRB050730 reported by Holland et al. (GCN 3704) \nand Sota et al. (GCN 3705) using the MIKE echelle spectrograph on Magellan II.\nThe observations started at UT 00:00:04 on July 31, 2005, ~ 4 hours after\nthe inital Swift/BAT trigger (GCN 3704).  We obtained a high signal-to-noise\n(S/N ~ 20 at 8000 Ang) spectrum with a resolution element of ~10 km/s.  We\nmeasure the afterglow at redshift z=3.967 based on a broad absorption trough  \nat 6040 Ang, which we identify as the Lya absorption line originated in the \nhost of the GRB.  We also detect a suite of strong absorption lines, which we \nconfirm as OI1302, SiII 1304, and CII 1334 at this redshift.    \n\nFurther analysis is underway.\n\nThis message may be cited.\"",
  "circularId": 3709,
  "createdOn": 1122774179000,
  "email": "hchen@space.mit.edu",
  "subject": "GRB 050730: Redshift Measurement based on Magellan/MIKE Observations",
  "submitter": "Hsiao-Wen Chen at MIT/CSR  <hchen@space.mit.edu>",
  "eventId": "GRB 050730"
}