{
  "bibcode": "2004GCN..2710....1R",
  "body": "Armin Rest (CTIO), James Rhoads (STScI), and Peter Weilbacher (Durham)\nreport on behalf of a larger collaboration:\n \nWe have observed the field of GRB 040912 using the 4m Blanco telescope\nand CCD Mosaic-2 camera at CTIO.  We obtained two epochs during the\nfirst night following the burst, at UT September 13.033 and 13.205.\nEach epoch consisted of four R band exposures of 300 seconds, for a\ntotal of 20 minutes' integration per epoch.  Conditions were\nphotometric but seeing was mediocre, at 1.35\" in the first epoch \nand 1.01\" in the second epoch.\n\nPreliminary image subtraction analysis reveals no compelling afterglow\ncandidates.  Our search is sensitive to a change in flux density of \n1.9 microJansky, which corresponds to the complete disappearance \nof an object with magnitude R=23.0",
  "circularId": 2710,
  "createdOn": 1095222986000,
  "email": "rhoads@stsci.edu",
  "subject": "GRB 040912: Optical Observations",
  "submitter": "James Rhoads at STScI  <rhoads@stsci.edu>",
  "eventId": "GRB 040912"
}