2010ApJS..187..251W

We present an ultradeep K_S-band image that covers 0.5x0.5 deg² centered on the Great Observatories Origins Deep Survey-North (GOODS-N). The image reaches a 5σ depth of {K_{S,AB}=24.45} in the GOODS-N region, which is as deep as the GOODS-N Spitzer Infrared Array Camera (IRAC) 3.6 µm image. We present a new method of constructing IRAC catalogs that uses the higher spatial resolution K_S image and catalog as priors and iteratively subtracts fluxes from the IRAC images to estimate the IRAC fluxes. Our iterative method is different from the χ² approach adopted by other groups. We verified our results using data taken in two different epochs of observations, as well as by comparing our colors with the colors of stars and with the colors derived from model spectral energy distributions of galaxies at various redshifts. We make available to the community our WIRCam K_S-band image and catalog (94,951 objects in 0.25 deg²), the Interactive Data Language pipeline used for reducing the WIRCam images, and our IRAC 3.6-8.0 µm catalog (16,950 objects in 0.06 deg² at 3.6 µm). With this improved K_S and IRAC catalog and a large spectroscopic sample from our previous work, we study the color-magnitude and color-color diagrams of galaxies. We compare the effectiveness of using K_S and IRAC colors to select active galactic nuclei and galaxies at various redshifts. We also study a color selection of z = 0.65-1.2 galaxies using the K_S, 3.6 µm, and 4.5 µm bands.