{
  "bibcode": "2009GCN.10100....1C",
  "body": "R. Chornock, D. A. Perley, and B. E. Cobb (UC Berkeley) report on behalf of a\nlarger collaboration:\n\nWe obtained optical spectra of the afterglow of GRB 091029 (Grupe et al., GCN\n10097; Filgas et al., GCN 10098; LaCluyze et al., GCN 10099) using GMOS on\nGemini-South.  Our spectra cover the wavelength range of 3900-8100 angstroms\nwith the R400 grating.  Our first 600s exposure, starting at 06:06 UT on Oct. 29\n(2.2 hr after the BAT trigger) reveals absorption lines from Lyman-alpha, C II,\nC IV, Si II, and Si IV at a common redshift of 2.752, which we identify as\nthe redshift of the GRB.  The afterglow is still quite bright (R~17.8 mag at\nt=2.02 hr) in the acquisition image.\n\nWe would like to thank German Gimeno and the Gemini staff for their assistance.",
  "circularId": 10100,
  "createdOn": 1256802559000,
  "email": "chornock@astro.berkeley.edu",
  "subject": "GRB 091029: Gemini-South Redshift",
  "submitter": "Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>",
  "eventId": "GRB 091029"
}