{
  "bibcode": "2013GCN.14445....1T",
  "body": "A. Trotter, N. Frank, A. LaCluyze, D. Reichart, K. McLin, L. Cominsky, \nT. Berger, H. T. Cromartie, R. Egger, A. Foster, J. Haislip, K. Ivarsen, \nM. Maples, J. Moore, M. Nysewander, E. Speckhard, and J. A. Crain report:\n\nSkynet continued observing the field of GRB 130420A (Page et al., GCN \n14406, Swift trigger #553977) with the 14\" GLAST Optical Robotic \nTelescope (GORT) at the Hume Observatory in California. It took 214 80-s \nexposures in Ic at times t=20.48-23.30h and t=26.25-28.56h after burst \ntrigger, and 96 80-s exposures in Rc at t=23.33-26.15h. We performed \nphotometry on the stacked exposures in each band, calibrated to six SDSS \nstars in the field. We detect the afterglow in both Ic and Rc bands at \nt~24h:\n\nband   exp length   mean time since trig   mag(Vega)\nIc     4.76h        24.37h                 21.04 (+0.43,-0.31)\nRc     2.47h        24.77h                 21.00 (+0.25,-0.21)\n\nAs we note in Trotter et al. (GCN 14427), and as Elenin et al. (GCN \n14428) confirm, the afterglow exhibits a rising light curve at early \ntimes, peaking at t=330s (peak Rc~16, Ic~15.5). After the peak, the \nlight curve fades with a power law index alpha~-0.9.\n\nA preliminary light curve of the first and second nights' data is at: \nhttp://skynet.unc.edu/grb/grb130420a_2.png",
  "circularId": 14445,
  "createdOn": 1366928365000,
  "email": "atrotter@physics.unc.edu",
  "subject": "GRB 130420A: Continued Skynet/GORT Observations/Detections",
  "submitter": "Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet  <atrotter@physics.unc.edu>",
  "eventId": "GRB 130420A"
}