{
  "bibcode": "2003GCN..2024....1B",
  "body": "R. Burenin, R. Sunyaev, M. Pavlinsky, D. Denissenko, O. Terekhov,\nA. Tkachenko (IKI); Z. Aslan, K. Uluc, I. Khamitov (TUG); U. Kiziloglu,\nA. Alpar, A. Baykal (METU); I. Bikmaev, N. Sakhibullin, V. Suleymanov (KSU)\n\nreport:\n\nThe optical afterglow of GRB 030329 (Peterson and Price, GCN 1985) was\nobserved with 1.5-m Russian-Turkish Telescope RTT150 at Bakyrlytepe (TUBITAK\nNational Observatory, Turkey). The observations started at Mar 29.744 UT,\nappr. 6 hours after the burst and lasted until Mar 30.061 UT, appr. 14 hours\nafter the burst.\n\nDuring the night we have obtained approximately 200 images in each BVRI\nBessel filter with 10-30 s exposures. The photometric conditions were good.\n\nTo calibrate the OT flux from the beginning of our observations we were\nusing the star which later was named as \"A\" star by Martini et al. (GCN\n2012). We assume this star is R=16.20 which agree well with our mean\nphotometric solution, obtained in previous nights. To calibrate OT flux in\nother filters we assume the following magnitudes of this star: B=18.22,\nV=17.02, I=15.42, measured using the same photometric solutions.\n\nThe optical transient showed no significant variations above the gradual\ndecline; the preliminary upper limit on short-term variability is 5%.\n\nIn the first 5 hours of our run we find that the R-band flux declines as\nt**-1.1. During the last 2.5 hours we observed the smooth continuous change\nin the slope of power law flux decay.\n\nThe fit of the post-break light curve reported by Garnavich et al. (GCN\n2018) lies exactly on the continuation of our light curve. This suggests\nthat we are lucky to observe in detail the major change in the slope of the\nlight curve and measure its duration. The break occured in 12-14 hours after\nthe burst and lasted for appr. 2-4 hours.\n\nThe R magnitudes of the afterglow are:\n       \nt-t0,hours   R\n 6.199\t    14.10\n 7.049\t    14.26\n 7.899\t    14.38\n 8.749\t    14.52\n 9.599\t    14.64\n10.449\t    14.75\n11.299\t    14.84\n12.149\t    14.96\n12.999\t    15.06\n13.849\t    15.16\n\nThe preliminary light curve in R can be found at\nhttp://hea.iki.rssi.ru/~br/lcl_030329_r.ps\n\nThe finding chart available at http://hea.iki.rssi.ru/~br/r_030329.gif\n\nFurther analysys of the lightcurve is underway. \n\nThis message may be cited.",
  "circularId": 2024,
  "createdOn": 1049037460000,
  "email": "rodion@hea.iki.rssi.ru",
  "subject": "GRB 030329: Light curve observed during the change of its slope.",
  "submitter": "Rodion Burenin at IKI, Moscow  <rodion@hea.iki.rssi.ru>",
  "eventId": "GRB 030329"
}