v 1 9 A pr 1 99 8 Near - Infrared Galaxy Counts to J and K ∼ 24 as a Function of Image Size

We have used the Keck 10m telescope to count objects as a function of image size in two high galactic latitude fields covering 1.5 arcmin and reaching 50% completeness depths of K=24 and J=24.5 for stellar sources. Our counts extend ∼1 magnitude deeper in K than those of surveys with other telescopes; complement other Keck surveys in the K band that provide counts at comparable or shallower depths but that have not utilized image structure; and extend by several magnitudes the J band counts from brighter surveys using smaller telescopes that cover larger areas. We find the surface-density of objects at K=23 to be higher than previously found (∼500,000 mag deg), but at K < 22 to be consistent with other surveys. The slope of the K band counts (dlogA/dm = 0.36) is similar to others near this depth as well as to our own J band counts (0.35). Counts in J and K bands are both in excess