{
  "bibcode": "2006GCN..4604....1H",
  "body": "GRB 060121: Probable Detection of NIR Afterglow\n\nF. Hearty (Colorado), M. Bayliss (Chicago), D. Q. Lamb (Chicago), G.\nGyuk (Chicago), M. Hammergren (Adler Planetarium), A. Puckett\n(Chicago), B. Ketzeback (APO), J. Barentine (APO), J. Dembicky (APO),\nR. McMillan (APO), and D. G. York (Chicago) report:\n\nWe observed the afterglow (Malesani et al. GCN 4561, Levan et al. GCN\n4562) of GRB 060121, a bright short/hard burst localized by HETE-2\n(Arimoto et al. GCN 4550, Prigozhin et al. GCN 4551, Boer et al. GCN\n4552), on the night of January 22nd, using NIC-FPS on the ARC 3.5-meter\ntelescope at Apache Point Observatory.  The observation began at 7.25\nUT on 23 January (32.83 hours after the burst) and ended at 8.63 UT on\n23 January (34.21 hours after the burst).  The observation consisted of\na series of 180 20-second exposures in Ks.  We have constructed from\nthem a stacked image of the GRB field, corresponding to a 60-minute\nexposure.  \n\nWe detect an object at the 5-sigma confidence level within 1\" of the \nlocation of the optical afterglow and well within the revised XRT\nerror circle (Mangano et al. GCN 4560).  The PSF of the object is\nconsistent with that of a point source.  We therefore identify the\nobject as the probable NIR afterglow of GRB 060121.  We measure Ks ~ 20\nmag, calibrated relative to four 2MASS stars in the field.\n\nExtended emission is visible about 1\" SE and NE of the probable NIR\nafterglow, but is detected at less than the 2-sigma confidence level.\nTherefore the emission might be due to nearby galaxies (possibly\nincluding the host of GRB060121) or merely to a background fluctuation. \nFurther observations are in progress.\n\nNIC-FPS is currently in its commissioning phase.",
  "circularId": 4604,
  "createdOn": 1138315850000,
  "email": "lamb@oddjob.uchicago.edu",
  "subject": "GRB 060121: Probable Detection of NIR Afterglow",
  "submitter": "Don Lamb at U.Chicago  <lamb@oddjob.uchicago.edu>",
  "eventId": "GRB 060121"
}