{
  "circularId": 14514,
  "submitter": "Nat Butler at Az State U  <natbutler@asu.edu>",
  "email": "natbutler@asu.edu",
  "subject": "GRB 130427A: Continued RATIR Optical and NIR Observations",
  "editedOn": 1731006005935,
  "body": "Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William\nH. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB)\nJ. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC),\nEleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC),\nJosé A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM),\nCarlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC)\nreport:\n\nWe again observed the field of GRB 130427A (Maselli, et al., GCN 14448)\nwith the Reionization and Transients Infrared Camera (RATIR; www.ratir.org)\non the 1.5m Harold Johnson Telescope at the Observatorio Astronómico\nNacional on Sierra San Pedro Mártir from 2013/04 30.14 to 2013/04 30.37 UTC\n(67.58 to 73.15 hours after the BAT trigger), obtaining a total of 3.91\nhours exposure in the r' and i' bands and 1.64 hours exposure in the Z, Y,\nJ, and H bands.\n\nWe continue to detect the optical/NIR afterglow (Elenin et al; GCN 14450)\nin all bands.  In comparison with SDSS DR8 and 2MASS, we find:\n\n  r'    19.39 +/- 0.01\n  i'    19.31 +/- 0.01\n  Z     18.89 +/- 0.03\n  Y     18.75 +/- 0.03\n  J     18.87 +/- 0.02\n  H     18.56 +/- 0.03\n\nThese magnitudes are in the AB system and not corrected for Galactic\nextinction in the direction of the GRB.  Uncertaints are 1-sigma.  The\nsource has faded by about 0.5 magnitude in all bands as compared to our\nmeasurements on the previous night (Butler et al. 2013; GCN 14506).\n\nWe thank the staff of the Observatorio Astronómico Nacional in San Pedro\nMártir.",
  "version": 2,
  "createdOn": 1367332975000,
  "format": "text/plain",
  "bibcode": "2013GCN.14514....1B",
  "eventId": "GRB 130427A",
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>"
}