{
  "bibcode": "2010GCN.10881....1N",
  "body": "H. Naito, T. Sako, D. Suzuki, S. Kobara and K. Omori (Nagoya Univ.) on  \nbehalf of the MOA Collaboration,\nT. Nagayama, M. Kurita (Nagoya Univ.) and N. Oi (The Graduate  \nUniversity for Advanced Studies/NAOJ)\non behalf of the IRSF Collabration report:\n\nWe searched for a NIR afterglow of GRB 100621A (Ukwatta et al., GCN  \n10870) starting from\n04:02 to 04:51 UT on 2010 June 21 with the SIRIUS on the IRSF 1.4m  \ntelescope at SAAO in\nSouth Africa. In images of a 300 sec exposure with J, H and Ks filter,  \nwe detected an new source\nwithin the error circle of the enhanced Swift XRT position (Evans et  \nal., GCN 10873) and at the\nlocation of the GROND source (Updike et al., GCN 10874) . The  \nestimated magnitudes are the\nfollowings.\n\n---------------------------------------------------------------\nMid time from   Total Exp.   J-mag*   H-mag*   K-mag*\ntrigger (min)     (s)\n---------------------------------------------------------------\n61.41                 300              16.56      15.22      14.18\n67.61                 300              16.24      14.63      13.84\n73.84                 300              15.27      13.78      12.63\n80.14                 300              15.07      13.57      12.40\n86.36                 300              14.93      13.45      12.23\n92.56                 300              14.90      13.45      12.32\n98.81                 300              14.93      13.47      12.34\n105.0                 300              15.04      13.55      12.36\n---------------------------------------------------------------\n*Typical error is ~ 0.1 mag\n\nThis photometry was done by using the DoPhot and calibrated against  \nthe 2MASS catalog stars,\nand not corrected for the Galactic extinction. The source was  \nbrightened up by >1mag during our\nobservation period while the other field stars were reasonably stable.",
  "circularId": 10881,
  "createdOn": 1277221041000,
  "email": "naito@stelab.nagoya-u.ac.jp",
  "subject": "GRB 100621A: IRSF/SIRIUS NIR Observation",
  "submitter": "Hiroyuki Naito at Nagoya U  <naito@stelab.nagoya-u.ac.jp>",
  "eventId": "GRB 100621A"
}