We present a 0.6−4.1 µm spectroscopic sequence of M, L, and T dwarfs. The spectra have R ≡ λ/∆λ ≈ 2000 from 0.9 to 2.4 µm and R=2500−200 from 2.9 to 4.1 µm. These new data nearly double the number of L and T dwarfs that have reported L-band spectra. The near-infrared spectra are combined with previously published redoptical spectra to extend the wavelength coverage to ∼0.6 µm. Prominent atomic and molecular absorption features are identified including neutral lines of Al, Fe, Mg, Ca, Ti, Na, and K and 19 new weak CH 4 absorption features in the H-band spectra of midto late-type T dwarfs. In addition, we detect for the first time the 0−0 band of the A 4 Π − X 4 Σ − transition of VO at ∼1.06 µm in the spectra of L dwarfs and the P and R branches of the ν 3 band of CH 4 in the spectrum of a T dwarf. The equivalent widths of the refractory atomic features all decrease with increasing spectral type and are absent by a spectral type of ∼L0, except for the 1.189 µm Fe I line which persists to

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We have conducted a 4030-square-deg near-infrared proper motion survey using multi-epoch data from the Two Micron All-Sky Survey (2MASS). We find 2778 proper motion candidates, 647 of which are not listed in SIMBAD. After comparison to DSS images, we find that 107 of our proper motion candidates lack counterparts at B-, R-, and I-bands and are thus 2MASS-only detections. We

We present the discovery of another seven Y dwarfs from the Wide-field Infrared Survey Explorer (WISE). Using these objects, as well as the first six WISE Y dwarf discoveries from Cushing et al., we further explore the transition between spectral types T and Y. We find that the T/Y boundary roughly coincides with the spot where the J − H colors of brown dwarfs, as predicted by models, turn back to the red. Moreover, we use preliminary trigonometric parallax measurements to show that the T/Y boundary may also correspond to the point at which the absolute H (1.6 µm) and W2 (4.6 µm) magnitudes plummet. We use these discoveries and their preliminary distances to place them in the larger context of the Solar Neighborhood. We present a table that updates the entire stellar and substellar constinuency within 8 parsecs of the Sun, and we show that the current census has hydrogen-burning stars outnumbering brown dwarfs by roughly a factor of six. This factor will decrease with time as more brown dwarfs are identified within this volume, but unless there is a vast reservoir of cold brown dwarfs -2invisible to WISE, the final space density of brown dwarfs is still expected to fall well below that of stars. We also use these new Y dwarf discoveries, along with newly discovered T dwarfs from WISE, to investigate the field substellar mass function. We find that the overall space density of late-T and early-Y dwarfs matches that from simulations describing the mass function as a power law with slope −0.5 < α < 0.0; however, a power-law may provide a poor fit to the observed object counts as a function of spectral type because there are tantalizing hints that the number of brown dwarfs continues to rise from late-T to early-Y. More detailed monitoring and characterization of these Y dwarfs, along with dedicated searches aimed at identifying more examples, are certainly required.2 Our team also maintains ancillary lists of candidates with bluer colors or fainter magnitudes, but those are beyond the scope of this paper. AAT/IRIS2The IRIS2 instrument (Tinney et al. 2004) at the 3.9m Anglo-Australian Telescope (AAT) at Siding Spring Observatory, Australia, provides wide-field imaging (7. ′ 7×7. ′ 7) using a 1024×1024 (0. ′′ 4486 pixel −1 ) Rockwell HAWAII-1 HgCdTe infrared detector. Our observation of WISE 2220−3628 used only the J filter, which is on the MKO-NIR system (Tokunaga et al. 2002). Data collection and reduction for this instrument are described in Tinney et al. (in prep.). CTIO/NEWFIRMThe NOAO Extremely Wide Field Infrared Imager (NEWFIRM; Swaters et al. 2009) at the 4m Victor M. Blanco Telescope on Cerro Tololo, Chile, uses four 2048×2048 InSb arrays arranged in a 2×2 grid. With a pixel scale of 0. ′′ 40 pixel −1 , this grid covers a total field of view of 27. ′ 6×27. ′ 6. Only one of our new Y dwarfs, WISE 0734−7157, was acquired with this instrument and it was observed only at J band, which is on the MKO-NIR system. Observing and reduction strategies are described in Kirkpatrick et al. (2011). SOAR/SpartanIRCThe Spart...