{
  "bibcode": "2003GCN..2019....1S",
  "body": "D. A. Smith reports on behalf of the ROTSE collaboration:\n\nThe ROTSE-IIIb instrument at McDonald Observatory in Texas began observing the\noptical counterpart to GRB 030329 as soon as it was possible to do so.  The\nfirst calibrated image began at 30 March 02:27:31 (UTC).  Images were\ncalibrated against the R-band magnitudes of the USNO A2.0 catalog, and the\nsource was initially found to be at an unfiltered magnitude of 15.35+-0.06 and\nfading.  Analysis of the first 70 images showed clearly that the rate of decay\nhad increased when compared to the observations recorded by ROTSE-IIIa the\nnight before (Rykoff & Smith, GCN Circ. 1995).  Separate power-law fits to each\ninstrument's data set indicated that the flux decay slope had shifted from\nabout 1.0 (consistent with the decay slope reported by Price, et al. GCN\nCirc. 2017) to about 1.9 (consistent with the decay reported by Garnavich et\nal. GCN Circ. 2018).  A plot of these decay curves along with the power-law\nfits can be seen at http://www.rotse.net/transients/grb030329/).  An\nextrapolation of these curves predicts a break time of about 12.1 h after the\nburst.  \n\nROTSE-IIIb will continue to observe GRB 030329 as long as it is able to do so.",
  "circularId": 2019,
  "createdOn": 1049012956000,
  "email": "dasmith@rotse2.physics.lsa.umich.edu",
  "subject": "GRB030329: ROTSE network observes steepening of decay curve",
  "submitter": "Don Smith at U michigan  <dasmith@rotse2.physics.lsa.umich.edu>",
  "eventId": "GRB 030329"
}