Search for a near-infrared counterpart to the Cassiopeia A X-ray point source

We report deep near-infrared and optical observations of the X-ray point so urce in the Cassiopeia A supernova remnant, CXO J232327.9 + 584842. We have identified a J = 21.4 +/- 0.3 mag and a K-s = 20.5 +/- 0.3 mag source with in the 1 sigma error circle, but we believe this source is a foreground Pop ulation II star with Teff = 2600-2800 K at a distance of approximate to 2 k pc that could not be the X-ray point source. We do not detect any sources i n this direction at the distance of Cas A and therefore place 3 a limits of R greater than or similar to 25 mag, F675W greater than or similar to 27.3 mag, J greater than or similar to 22.5 mag, and K-s greater than or simila r to 21.2 mag (and roughly H greater than or similar to 20 mag) on emission from the X-ray point source, corresponding to M-R greater than or similar to 8.2 mag, M-F675W greater than or similar to 10.7 mag, M-J greater than o r similar to 8.5 mag, M-H greater than or similar to 6.5 mag, and M-Ks grea ter than or similar to 8.0 mag, assuming a distance of 3.4 kpc and an extin ction of A(V) = 5 mag.