A Near‐Infrared Imaging Survey of the ρ Ophiuchi Cloud Core

We present results of the largest three-color near-infrared (NIR) imaging survey of the o Ophiuchi star-forming cloud core to date. The survey covers 1 deg2, which corresponds to a projected area of D2.2 pc ] 2.2 pc at the distance of the Ophiuchus clouds (125 ^25 pc). Mapping was carried out in the J (1.25 km), H (1.63 km), and K (2.22 km) bands, to 90%, 10 p completeness limits of J \ 15.0, H \ 14.5, and K \ 14.0. We have cataloged 4495 sources, of which 2070 have K 14.0 and 2425 more either have 5 p or better detections in the K band (for 14.0 K 14.5) or have 4 p or better detections in at least two of the three survey bands (for K 14.5). We present accurate astrometry and photometry for all identied sources. We also tabulate cross-identications for 449 previously observed NIR sources. Using the cross-identications, we derive linear transformations between the di ering photometric systems and use rather strict criteria to identify NIR variables.