Exploring the 2MASS Extended and Point Source Catalogs with Clustering
  Redshifts
  The Two-Micron All-Sky Survey (2MASS) has mapped out the low-redshift
Universe down to $K_S\sim14$ mag. As its near-infrared photometry primarily
probes the featureless Rayleigh-Jeans tail of galaxy spectral energy
distributions, colour-based redshift estimation is rather uninformative. Until
now, redshift estimates for this dataset have relied on optical follow-up
suffering from selection biases. Here we use the newly-developed technique of
clustering-based redshift estimation to infer the redshift distribution of the
2MASS sources regardless of their optical properties. We characterise redshift
distributions of objects from the Extended Source Catalogue as a function of
near-infrared colours and brightness and report some observed trends. We also
apply the clustering redshift technique to dropout populations, sources with
non-detections in one or more near-infrared bands, and present their redshift
distributions. Combining all extended sources, we confirm with clustering
redshifts that the distribution of this sample extends up to $z\sim0.35$. % We
perform a similar analysis with the Point Source Catalogue and show that it can
be separated into stellar and extragalactic contributions with galaxies
reaching $z\sim0.7$. We estimate that the Point Source Catalogue contains 1.6
million extragalactic objects: as many as in the Extended Source Catalogue but
probing a cosmic volume ten times larger.
