TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4753 SUBJECT: GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy DATE: 06/02/13 04:27:48 GMT FROM: Don Lamb at U.Chicago GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy F. Hearty (Colorado), M. Bayliss (Chicago), D. Q. Lamb (Chicago), R. McMillan (APO), B. Ketzeback (APO), J. Barentine (APO), J. Dembicky (APO), and D. G. York (Chicago) report: We observed the afterglow (Fox and Cenko, GCN 4723; Li, GCN 4725, 2727; Williams and Milne, GCN 4728, 4730; Misra, GCN 4742) of GRB 060210, a bright burst localized by Swift (Beardmore et al. GCN 4724, 4733; Takamoto et al. GCN 4748), on the night of February 10, using NIC-FPS on the ARC 3.5-meter telescope at Apache Point Observatory. The observation began at 2.65 UT on 11 February (21.75 hours after the burst) and ended at 3.35 UT on 11 February (22.37 hours after the burst). The observation consisted of a series of 90 20-second exposures in Ks. Using these exposures, we have constructed a stacked image of the GRB field, corresponding to a 30-minute exposure. Further 20-second exposures amounting to a total of 3300 seconds of exposure were taken immediately following this and are being processed. We detect an object at greater than the 5-sigma confidence level at the location of the optical afterglow to within 0.5". The PSF of the object overlaps with that of an adjacent extended source, but appears to be consistent with that of a point source. We identify the object as the NIR afterglow of GRB 060210. We measure Ks = 19.3 ± 0.2 mag, calibrated relative to the 2MASS stars in the field. We also detect an extended object centered 2"-3" to the north and immediately adjacent to the afterglow at Ks = 20.2 ± 0.3 mag, which may be the host galaxy of the burst. NIC-FPS is currently in its commissioning phase.