{
  "bibcode": "2007GCN..6259....1B",
  "body": "J. S. Bloom (UC Berkeley), H-W. Chen (Chicago), J. X. Prochaska (UC  \nSanta Cruz), N. R. Bulter (UC Berkeley) report:\n\nWe observed the field of GRB 070406 (Cummings et al.; GCN 6247) with  \nthe GMOS instrument on Gemini South in r and i-band filters. An i- \nband finder is provided (*) with mean epoch 7.26 April 2007 UT (~29.4  \nhours after the GRB). The images cover the region of the XRT source  \n(Troja et al.; GCN 6255). Our re-analysis of the XRT data, based on  \nthe first 20 ks and allowing for the possiblity of an astrometric XRT  \nframe offset, yields a moderately larger XRT error circle (labeled  \n\"Butler\") of:\n\n        RA(J2000) =  13:15:51.16  DEC =  +16:30:47.7  (6.4\" at 90%  \nconfidence)\n\nWe cannot confirm any variability of the X-ray source. The SDSS  \ngalaxy noted by Kann (GCN 6256) and the faint source noted by  \nMalesani et al. (GCN 6257) are well detected. We note that the  \nMalesani source appears to be resolved and it thus unlikely to be the  \nafterglow (it also appears marginally detected in the SDSS i-band  \nimage from Cool et al. GCN 6248). We note 5 additional sources in the  \nXRT error circle (J2000):\n\n                 RA                  DEC\n    s1   13:15:51.41  +16:30:42.6\n    s2   13:15:51.19  +16:30:41.9\n    s3   13:15:50.94  +16:30:42.6\n    s4   13:15:50.75  +16:30:48.0\n    s5   13:15:51.48  +16:30:52.7\n\nWe make no claims about variability at this time.\n\nWe find no source at the location of the Xin et al. transient (GCN  \n6253). However, we do detect a faint source ~2.3 arcseconds to the  \nSouth West of that position at:\n\n    OT?  13:15:40.91  16:34:13.1\n\nThis source is several magnitudes fainter than the galaxy to the  \nnorthwest noted by Xin et al., whereas Xin et al. indicate that their  \nsource was 4 magnitudes brighter at 35.4 hour after the GRB.\"\n\nThis message can be cited.\n\n(*) http://lyra.berkeley.edu/~jbloom/grb070406_ep1.pdf\n\nGRAASP thanks to Henry Lee and the observing team at Gemini South for  \nperforming these ToO observations.",
  "circularId": 6259,
  "createdOn": 1176008748000,
  "email": "jbloom@astron.berkeley.edu",
  "subject": "GRB 070406: Gemini South Imaging and XRT analysis",
  "submitter": "Josh Bloom at UC Berkeley  <jbloom@astron.berkeley.edu>",
  "eventId": "GRB 070406"
}