{
  "bibcode": "2005GCN..3540....1R",
  "body": "James Rhoads reports on behalf of a larger collaboration:\n\nWe observed the afterglow of GRB 050607 with the 4m Mayall Telescope\nof Kitt Peak National Observatory from UT 2005 June 8 10:33 to 11:05.\nWe obtained three I band exposures with total integration time\nof 26 minutes.  The GRB counterpart is weakly detected in the sum\nof the three images, with a statistical error around 0.2 to 0.25\nmagnitudes.\n\nRelative photometry with respect to a nearby field star\nshows that the transient has faded by 2.3 +- 0.2 magnitudes\nbetween t=640 seconds and t=92300 seconds post-trigger.\n\nBased on a power law fit to the night 1 data (Rhoads, GCNC 3531),\nwith decay slope 0.5, we would expect a fading of 2.9 magnitudes\nover the same period.   This suggests that host galaxy light may\nbe contributing detectably to our most recent flux measurement.\nHowever, the statistical significance of this excess is low.\nA single power law fit to the combined night one and night two\ndata has a time decay slope of 0.4 and nearly acceptable residuals.\nIf we exclude the first point (t=640 seconds) from the fit, on the\nsupposition that the physics dominating the afterglow changed\naround 1e3 seconds, the decay slope in our other UT 050607 data\nbecomes 0.3 and the UT 050608 point lies precisely on this shallow,\nextrapolated decay.\n\nAdditional data would help distinguish among these possibilities,\nand further monitoring is encouraged.",
  "circularId": 3540,
  "createdOn": 1118287222000,
  "email": "rhoads@stsci.edu",
  "subject": "GRB 050607 optical decay",
  "submitter": "James Rhoads at STScI  <rhoads@stsci.edu>",
  "eventId": "GRB 050607"
}