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.