{
  "bibcode": "2017GCN.21954....1I",
  "body": "R. Itoh (Tokyo Tech), K. L. Murata (Tokyo Tech), K. Morihana (Nagoya U.)\nand T. Nagayama (Kagoshima U)\n\nWe observed the field of GRB 171001A (Lien et al., GCNCircular #21946) with\nthe near-infrared (J, H, Ks) simultaneous imaging camera SIRIUS attached to\n1.4 m telescope IRSF (InfraRed Survey Facility) in Sutherland observatory,\nSouth Africa.\n\nThe observations started on 2017-10-01 19:16:51 UT. We detected the\nafterglow within the enhanced XRT error circle (Evans et al., GCN Circular\n#21952) in J band. The measured magnitudes (Vega magnitude system) were\nlisted as below.\n\nT0+[min]    MID-UT      T-EXP[sec]        J                 H\nKs\n-------------------------------------------------------------------------------------------------\n~48         19: 31              1270            17.0+-1.1      >16.3\n>16.0\n-------------------------------------------------------------------------------------------------\nT0+ : Elapsed time after the burst\nT-EXP: Total Exposure time\n\nGiven magnitudes were calibrated against 2MASS point sources in this field.\n\nThis observation was carried out by IRSF and OISTER collaboration.",
  "circularId": 21954,
  "createdOn": 1506906471000,
  "email": "murata@u.phys.nagoya-u.ac.jp",
  "subject": "GRB 171001A: IRSF Observation",
  "submitter": "Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>",
  "eventId": "GRB 171001A"
}