{
  "bibcode": "2006GCN..5260....1K",
  "body": "Agata Karska and Peter Garnavich (Notre Dame)\n\nWe observed the position of GRB 060605 (Rykoff et al., GCN 5220)\nwith the Vatican Advanced Technology Telescope (VATT) and 2KCCD\ncamera on 2006 June 6.44 UT (16.3 hours after the burst).\nThree R-band images, each with an exposure time of 300s, were\ncombined and a source detected at the Swift/UVOT position\n(Page et al., GCN 5221).\n\nUsing an average of five USNO-B1.0 stars (magR1) to set the\nzero-point we estimate the brightness of the afterglow at\nR=21.5 +/- 0.2 mag.\n\nWe note that the USNO-B1.0 magR2 values for the star used\nby Khamitov et al. (GCN 5224, 5235) and for other stars in the field\nprovide an inconsistent zero-point with variations of 0.6 mag\nwhen compared to the instrumental magnitudes of our R-band image.\nHowever, the magR1 estimates for the five star are consistent\nto 0.1 mag.\n\nAssuming the same calibration as Khamitov et al. (shifting our\nGRB magnitude fainter by 0.7 mag) provides a power law decay index\nof 2.1 between 6 and 16 hours after the burst. Adding the Khamitov et al.\nobservation 31 hours after the burst significantly decreases the\ndecay slope and may indicate contamination from the host galaxy.\n\nThis burst was observed by the Spitzer Space Telescope and any additional\nphotometry would be useful in interpreting the infrared data.\n\nThis message may be cited.",
  "circularId": 5260,
  "createdOn": 1150386939000,
  "email": "pgarnavi@nd.edu",
  "subject": "GRB 060605, optical observations",
  "submitter": "Peter Garnavich at U of Notre Dame  <pgarnavi@nd.edu>",
  "eventId": "GRB 060605"
}