{
  "bibcode": "2004GCN..2597....1F",
  "body": "D.B. Fox, E. Berger and D. Moon (Caltech), with K. von Braun and\nB. Lee (Carnegie), report: \n\n\"We have imaged the SXC localization region for GRB040511 (Dulligan et\nal., GCN 2588) in the J-band with the Dupont telescope + WIRC imager\nat Las Campanas Observatory, on two occasions.  Our first-night\nimaging consists of 21 minutes' exposure at mean epoch May 12.05 UT\n(12.2 hours post-burst) in 1\" seeing; our second-night imaging\nconsists of 15 minutes' exposure at mean epoch May 13.35 UT (43.4\nhours post-burst) in 0.75\" seeing.\n\nPSF-matched image subtraction of the combined images from these two\nnights reveals a single source within the SXC region that fades\nsignificantly between the two epochs, from J~19.0 mag to J~20.9 mag as\nreferenced to 2MASS photometry of the field.  Since the source is also\nobserved to fade (by ~1.3 mag) in the contemporaneous (t+11 hour and\nt+36 hour, respectively) R-band imaging of Morrell et al. (GCN 2594)\nand Chen et al. (GCN 2591), we conclude that it is a likely afterglow\ncandidate.  The source coordinates are:\n\n    RA 14:47:49.33,  Dec -44:14:21.8 (J2000)\n\nas referenced to 2MASS catalog astrometry; the uncertainty in this\nposition is < 0.5\".  The image-pixel coordinate position of the\ncandidate on the first-epoch imaging of Chen et al. (see\nhttp://www.graasp.org/, \"DATA\" section, file \"grb040511_R1.fits\") is\nX=1214.6, Y=1463.8.\n\nThe authors would like to express their gratitude to the the Carnegie\nSupernova Program for this allocation of time, and to the GRAASP\ncollaboration for the public release of their data in FITS format.",
  "circularId": 2597,
  "createdOn": 1084499483000,
  "email": "derekfox@astro.caltech.edu",
  "subject": "GRB040511: Candidate optical/NIR afterglow",
  "submitter": "Derek Fox at CIT  <derekfox@astro.caltech.edu>",
  "eventId": "GRB 040511"
}