{
  "bibcode": "2007GCN..6756....1T",
  "body": "Christina C. Thoene (DARK, UC Berkeley), Joshua S. Bloom, Nathaniel R.\nButler (UCB) and Peter Nugent (LBL) report:\n\nWe obtained spectra of several sources around the reported XRT positions\nof GRB70810B (GCN 6754 , Starling et al.) on Aug. 11, 12:30 UT, using Keck\nI + LRIS. No new source is seen in imaging of the field at the same time.\nAt the position of source 1 (\"S1\") from Starling et al., there is no\noptical counterpart visible. From further analysis of the X-ray data, we\ndetect another weak X-ray source at RA 00:35:46.892, DEC 08:51:05.96\n(\"S3\") which includes a weak optical source.\nWithin the BAT error circle, there is an early type galaxy (LEDA 1354367)\nas noted first in Marshall et. al, GCN 6743, for which we determined a\nredshift of z=0.0385 derived from Ca H&K absorption lines.\nAround source 2 (\"S2\"), there are four galaxies of which two show strong\nemission lines leading to a redshifts around z=0.49 from OII, OIII and the\nBalmer series. The two other galaxies have marginal detections of emission\nlines at the same redshift and these galaxies might therefore be part of a\ncluster or even interacting.\n\nAn image indicating the different XRT positions and galaxies observed can\nbe found at:\nhttp://lyra.berkeley.edu/~cthoene/GRBs/GRB070810B.png\n\n\nCT wants to thank Keck support astronomer Greg Wirth and his wife for\nexcellent dinner support during the observations. Tusend tak!",
  "circularId": 6756,
  "createdOn": 1186889102000,
  "email": "cthoene@astro.ku.dk",
  "subject": "GRB 070810B: Keck spectroscopy of possible host galaxies",
  "submitter": "Christina Thoene at Niels Bohr Institute,DARK Cosmo Ctr  <cthoene@astro.ku.dk>",
  "eventId": "GRB 070810B"
}