{
  "bibcode": "2010GCN.10443....1C",
  "body": "S. B. Cenko, J. S. Bloom, D. A. Perley, and B. E. Cobb (UC Berkeley)\nreport on behalf of a larger collaboration:\n\nWe have obtained spectra of the proposed host galaxy (Bloom and\nNugent, GCN 10433; Holland et al., GCN 10436) and the optical afterglow\n(Jakobsson et al., GCN 10438; Kruehler et al., GCN 10439) of\nGRB100219A (Rowlinson et al., GCN 10430) with the Gemini Multi-Object\nSpectrograph mounted on the 8-m Gemini South telescope.  Our first\nsequence of 2 x 900 s observations started at 2:44 UT on 20 February\n2010 and cover the range from 6500 - 9500 A.  Only the proposed host\ngalaxy was contained on the slit for these spectra.  Our second set,\nstarting immediately afterward, cover the wavelength range from 4500 -\n7500 A and both the proposed host and afterglow are positioned on the\nslit.\n\nFrom the nearby galaxy, we detect strong emissions features corresponding\nto H-alpha, H-beta, and [O III] at a common redshift of z = 0.217.\n\nThe spectrum of the afterglow shows a strong break at ~ 6880 A, with\nonly faint continuum blueward of this feature.  Interpreting this as\nthe Lyman-alpha break, this correponds to a redshift of z ~ 4.7.  We\nfind marginal evidence for narrow absorption features corresponding to Si\nII and Si II* at z = 4.65 redward of the break - however the relatively\nlow signal-to-noise ratio of our spectrum in this regime makes this result\nsomewhat uncertain.\n\nOur derived redshifts for both objects are similar to, though slightly\nless than, the values derived by Groot et al. (GCN 10441) from the\nVLT/X-shooter.  They are also consistent with the photometric redshift of\nz ~ 4.5 derived by Kruehler et al. (GCN 10439) from GROND.",
  "circularId": 10443,
  "createdOn": 1266649132000,
  "email": "cenko@srl.caltech.edu",
  "subject": "GRB 100219A - Gemini South Spectroscopy",
  "submitter": "S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>",
  "eventId": "GRB 100219A"
}