{
  "bibcode": "2015GCN.17788....1M",
  "body": "K. L. Murata (Nagoya U.), S. Nishiyama, A. Iwamatsu, I. Kawamata (Miyagi\nUniversity of Education), and T. Nagayama (Kagoshima U.)\n\nWe observed the field of GRB 150428B ( Page et al., GCN Circular #17766) with\nthe near-infrared (J, H, Ks) simultaneous imaging camera SIRIUS attached to 1.4\nm telescope IRSF ( InfraRed Survey Facility) in Sutherland observatory, South\nAfrica.\n\nThe observations started on 2015-04-28 03:59:59 UT (~ 48 min. after the burst).\nWe could not detect the afterglow within the XRT error circle reported in the\nGCN circular in the three bands.\nWe have obtained the following preliminary upper limits (Vega magnitude system):\n J  > 17.4\n H  > 16.8\n Ks > 15.3.\n\nGiven magnitudes were calibrated against 2MASS point sources in this field.\nThe upper limits were determined as the magnitudes of the faintest star within 1\narcmin from the XRT position.\n\nThis observation was carried out by IRSF and OISTER collaboration.",
  "circularId": 17788,
  "createdOn": 1430350811000,
  "email": "dikuroda@oao.nao.ac.jp",
  "subject": "GRB 150428B: IRSF NIR upper limits",
  "submitter": "Daisuke Kuroda at OAO/NAOJ  <dikuroda@oao.nao.ac.jp>",
  "eventId": "GRB 150428B"
}