Ultradeep Ks imaging in the GOODS-N

The image reaches a 5{sigma} 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) 3.6um 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 {chi}^2^ 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 (94951 objects in 0.25deg^2^), the Interactive Data Language pipeline used for reducing the WIRCam images, and our IRAC 3.6-8.0um catalog (16950 objects in 0.06deg^2^ at 3.6um).