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We present the culmination of our near-infrared survey of the optically spectroscopically identified white dwarf stars from the McCook & Sion catalog, conducted using photometric data from the Two Micron All Sky Survey final All Sky Data Release. The color-selection technique, which identifies candidate binaries containing a white dwarf and a low mass stellar (or sub-stellar) companion via their distinctive locus in the near-infrared color-color diagram, is demonstrated to be simple to apply and to yield candidates with a high rate of subsequent confirmation. We recover 105 confirmed binaries, and identify 28 firm candidates (20 of which are new to this work) and 21 tentative candidates (17 of which are new to this work) from the 2MASS data. Only a small number of candidates from our survey have likely companion spectral types later than M5, none of which is an obvious L type (i.e., potential brown dwarf) companion. Only one previously known WD + brown dwarf binary is detected. This result is discussed in the context of the 2MASS detection limits, as well as other recent observational surveys that suggest a very low rate of formation (or survival) for binary stars with extreme mass ratios.
We introduce the properties of the Two Micron All-Sky Survey (2MASS) survey for IAU Symposium 204. 2MASS is a near-infrared survey of the entire sky characterized by high reliability and completeness. Catalogs and images for 47% of the sky are now av
We present two confirmed wide separation L-dwarf common proper motion companions to nearby stars and one candidate identified from the Two Micron All Sky Survey. Spectral types from optical spectroscopy are L0 V, L2.5 V, and L8 V. Near-infrared low r
Using data from the 2MASS All-Sky Point Source Catalogue, we have extended our census of nearby ultracool dwarfs to cover the full celestial sphere above Galactic latitute 15 degrees. Starting with an initial catalogue of 2,139,484 sources, we have w
We report the discovery of 9 089 new spectroscopically confirmed white dwarfs and subdwarfs in the Sloan Digital Sky Survey Data Release 10. We obtain Teff, log g and mass for hydrogen atmosphere white dwarf stars (DAs) and helium atmosphere white dw
We have analyzed the rotational properties of 12 clumps using $^{13}$CO (1--0) and C$^{18}$O (1--0) maps of the Five College Radio Astronomy Observatory 13.7 m radio telescope. The clumps, located within molecular clouds, have radii ($R$) in the rang