{
  "bibcode": "2003GCN..2255....1C",
  "body": "We have noticed a minor numerical error near the end of GCN 2254.  Here\nis a corrected (and slightly expanded) version:\n\nH. Cheng, M. Bayliss, D. Reichart, J. Moran, M. Nysewander, M. Schwartz,\nand P. Holvorcem report on behalf of the UNC GRB team of the FUN GRB\ncollaboration:\n\nWe observed the afterglow (Peterson & Price, GCN 1985) of GRB 030329\n(Vanderspek et al., GCN 1997) with the 32-inch Tenagra II telescope in\nIcRcVIc on April 2nd and 3rd, in IcIc on April 4th and 5th, and in Ic on\nApril 6th, 7th, 8th, 9th, and 10th.  Between April 2nd and 10th, we find\nthat the afterglow faded from Ic = 16.9 mag to Ic = 18.9 mag.  Our error\nbars are typically less than 0.02 mag (1 sigma).\n\nFitting a four-parameter model to the data, where the parameters are the\ntemporal index alpha, the spectral index beta, a normalization parameter,\nand a parameter that measures the level of systematic (i.e.,\nnon-statistical) fluctuations in the light curve, we find that alpha =\n-1.70(+0.13)(-0.14), beta = -1.38(+0.20)(-0.20), and that the fading\nafterglow is fluctuating at the 17.5(+3.8)(-3.5)% level at these times.\n\nFurthermore, these fluctuations appear to be chromatic in nature.\n\nWe note that the measured spectral index is too steep given the measured\ntemporal index and the post-jet break time relations of Sari, Piran, &\nHalpern (1999, ApJ, 519, L17).  Possible explanations include:\n\n1. The light curve had not yet reached its asymptotic temporal index, which\nif the afterglow is unextinguished would be alpha = -2.76 +- 0.40 if the\ncooling break is redward of the observed bands or alpha = -3.76 +- 0.40 if\nthe cooling break is blueward of the observed bands; or\n\n2. The light curve is extinguished.  Although this does not appear to be\nthe case at earlier times, this could be the case at later times if dust\nwas destroyed within the initial opening angle of the jet, but then the jet\nexpanded laterally behind undisturbed dust.",
  "circularId": 2255,
  "createdOn": 1054153582000,
  "email": "hawcheng@physics.unc.edu",
  "subject": "GRB 030329: Correction to GCN 2254",
  "submitter": "Haw Cheng at UNC  <hawcheng@physics.unc.edu>",
  "eventId": "GRB 030329"
}