{
  "bibcode": "2003GCN..2017....1P",
  "body": "P.A. Price, B.P. Peterson and B.P. Schmidt (RSAA, ANU) report:\n\nSynthesis of observations from Rykoff et al. (GCN #1995), Gal-Yam et\nal. (GCN #1999), Martini et al. (GCN #2012) and from the SSO 40-inch\n(GCN #1987) yeilds the following decay:\n\n\tR/mag ~ 15.8 + 2.4 log (t/days)\n\nwith corresponding power-law index alpha = 0.97 +/- 0.03.\nHence, though the afterglow is bright, the decay is not unusually\nshallow (eg, 010222 had alpha1 ~ 0.80).\n\nThe spectral index, calculated from the B-I colour from Burenin et\nal. (GCN #2001) and Rumyantsev et al. (GCN #2005) is beta ~ 1.2.\n\nUsing the measured redshift (Martini et al., GCN #2013; Della Ceca et al.,\nGCN #2015), optical decay and spectral index, we calculate the R-band\nabsolute magnitude of the optical afterglow for t=1 day in the source\nframe, M_R,1 = -26.7 mag.  This is therefore the most intrinsically bright\noptical afterglow observed to date (with 000301C and 000418 tied for\nsecond at M_R,1 = -26.1 mag).  The low redshift and the large intrinsic\nbrightness combined to produce an optical afterglow with a large apparent\nbrightness.\n\nThe redshift of z=0.57 and measured fluence (Vanderspek et al., GCN #1997)\nimplies an isotropic-equivalent energy release of 1.1 x 10^53 erg (30-400\nkeV).  The Frail et al. \"standard energy\" result implies a jet-break time\nof around 4 days.  At this time, the afterglow should be R ~ 17.3 mag.\nWe encourage polarimetric observations to be made on this timescale to\nconstrain the jet dynamics.\n\nThis message may be cited.",
  "circularId": 2017,
  "createdOn": 1049011024000,
  "email": "pap@mso.anu.edu.au",
  "subject": "GRB 030329: Optical decay and synthesis",
  "submitter": "Paul Price at RSAA, ANU  <pap@mso.anu.edu.au>",
  "eventId": "GRB 030329"
}