TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5126 SUBJECT: GRB 060512: Detection of NIR afterglow DATE: 06/05/13 07:50:38 GMT FROM: Don Lamb at U.Chicago GRB 060512: Detection of NIR afterglow F. Hearty (Colorado), D. Q. Lamb (Chicago), R. McMillan (APO), J. Bally (Colorado), G. Wolf-Chase (Chicago), H.-W. Chen (Chicago), D. G. York (Chicago), M. Bayliss (Chicago), B. Ketzeback (APO), J. Barentine (APO), and J. Dembicky (APO) report: We have observed the afterglow (Cummings et al, GCN 5117; Mundell and Steele, GCN 5118; Malesani et al., GCN 5122; Cenko, GCN 5125) of GRB 060512, a bright burst localized by Swift BAT (Cummings et al., GCNs 5117, 5124), beginning at about 5:36 UT on 13 May 2006 (about 6.4 hours after the burst) under partly cloudy conditions, using NIC-FPS on the ARC 3.5-meter telescope at Apache Point Observatory. The observation consisted of a series of 15 20-second exposures in Ks. From them, we have constructed a stacked image of the GRB field, corresponding to a 5-minute exposure. We measure a magnitude for the afterglow of Ks = 17.7 +/-0.2. Further observations are underway. NIC-FPS is currently in its commissioning phase.