{
  "bibcode": "2013GCN.14456....1P",
  "body": "D. A. Perley (Caltech) and S. B. Cenko (UC Berkeley) report:\n\nWe have continued observations of the afterglow of GRB130427A (Maselli et\nal., GCN 14448) with the Palomar 60-inch telescope until the field set.\nRelative to SDSS reference stars in the field, in some select recent\nimages we estimate afterglow magnitudes of:\n\nr' = 14.86 mag  (t = 1.40 hours)\nr' = 15.32 mag  (t = 2.31 hours)\nr' = 15.55 mag  (t = 3.10 hours)\n\nThis is brighter (by about 1 mag) than any other Swift burst as measured\nat similar epoch (as of 2010; Kann et al. ApJ 720:1513), though still\nsignificantly fainter than GRB 030329 which reached approximately 13 mag\nat 0.1 day.  The rate of fading corresponds to a relatively shallow decay\nindex of approximately alpha~-0.85, suggesting that this afterglow will\nremain bright for an extended period.  Worldwide small-telescope follow-up\n(including by amateurs) is strongly encouraged.",
  "circularId": 14456,
  "createdOn": 1367063564000,
  "email": "cenko@srl.caltech.edu",
  "subject": "GRB 130427A: Continued P60 follow-up of an extremely bright optical afterglow",
  "submitter": "S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>",
  "eventId": "GRB 130427A"
}