{
  "bibcode": "2003GCN..2168....1D",
  "body": "Optical Observations of GRB 030418 with Magellan\n\nA. Dullighan, N. R. Butler, G. R. Ricker, J. L. Elliot, K. Clancy \n(MIT), and D. Osip (Las Campanas Observatory)\n\nreport:\n\nOn 2003 April 21.01 UT, we observed the optical afterglow (Price et \nal; GCN2148) of the HETE-localized GRB 030418 (=H2686) with the \nMagellan 6.5 meter Clay telescope at Las Campanas Observatory in \nChile.  Our observations consisted of three 300s R-Band images and \none 300s I-Band image, taken with the MagIC instrument.  The \nafterglow brightness had declined significantly since the \nmeasurement reported in GCN2148, consistent with a power law decay \nindex = 1.3+/-0.1. The afterglow was still point-like in our images, \nwith a FWHM of 0.5 arcsec. Our results were as follows:\n\nUT                 t-t0 (days)    Mag\n2003-04-21.02      2.60           R=23.64 +/- 0.07\n2003-04-21.03      2.61           I=22.60 +/- 0.05\n\nThe magnitudes reported above are relative to those of the USNO B1 \ncatalog star at RA = 10h 54m 32.71s, Dec = -07:02:16.4 (J2000), taken \nas having R=19.33 and I=18.31. Magnitude errors for the USNO star \nwere not available, and so are not included in the errors we report \nhere.  Possible errors in the magnitudes of the USNO catalog star \nshould be taken into account when comparing our afterglow magnitudes \nto other measurements. Further observations are planned.\n\nThis message may be cited.",
  "circularId": 2168,
  "createdOn": 1051233103000,
  "email": "grr@space.mit.edu",
  "subject": "Optical Observations of GRB 030418 with Magellan",
  "submitter": "George Ricker at MIT  <grr@space.mit.edu>",
  "eventId": "GRB 030418"
}