{
  "bibcode": "2005GCN..3417....1B",
  "body": "Correction: in GCN circular #3416 we inadvertently left out reference to\nthe Chandra observations (Burrows et al. #3415). Below is the corrected\ncircular. We apologize for the reference omission.\n\n ---------------------------\nJ. S. Bloom, R. J. Foley, D. Pooley, A. V. Filippenko, R. Chornock (UCB),\nC. Blake (Harvard), J. X. Prochaska (UCSC), J. Hennawi (UCB), M. Gladders\n(Carnegie), B. Koester (U Michigan) and H. W. Chen (MIT) report:\n\nWe observed the field of GRB 050509b (#3383,#3385) with Keck I (+LRIS)\nwith g' and R filters.  Starting at 20050511.25 UT, we took 5 dithered\nimages in each band for a total of 1660 and 1620 sec exposures in g and R,\nrespectively. At the location of the two reported Chandra sources (Burrows\net al. GCN #3415) we find no significantly-detected flux in either band,\nhowever there are indications of an R counterpart (at the few sigma level)\nto Chandra #8. Moreover, these images do reveal a number of sources in the\nXRT error circle fainter than in reported deep imaging with the VLT\n(#3410) and Keck I (#3401), which we label J1-J4:\n\n   J1 12:36:13.56 +28:59:03.4\n   J2       13.44        04.7\n   J3       13.41     58:56.3\n   J4       13.47     59:06.2\n\n(J2000; estimated errors of 0.3 arcsec in each direction).\n\nWe note that S5, which is less than 2 arcsec from the Chandra source #5,\nappears bluer than neighboring S3 and S2.\n\nThe finding chart can be found at:\n http://astro.berkeley.edu/~jbloom/grb050509b-chandra-keck-combo.gif",
  "circularId": 3417,
  "createdOn": 1115890853000,
  "email": "jbloom@cfa.harvard.edu",
  "subject": "GRB 050509b: Keck/Chandra Cross-Correlation",
  "submitter": "Josh Bloom at Harvard/CFA  <jbloom@cfa.harvard.edu>",
  "eventId": "GRB 050509B"
}