Characterization of M, L, and T Dwarfs in the Sloan Digital Sky Survey

An extensive sample of M, L and T dwarfs identified in the Sloan Digital SkySurvey (SDSS) has been compiled. The sample of 718 dwarfs includes 677 newobjects (629 M dwarfs, 48 L dwarfs) together with 41 that have been previouslypublished. All new objects and some of the previously published ones have newoptical spectra obtained either with the SDSS spectrographs or with the ApachePoint Observatory 3.5m ARC telescope. Spectral types and SDSS colors areavailable for all objects; approximately 35% also have near-infrared magnitudesmeasured by 2MASS or on the Mauna Kea system. We use this sample tocharacterize the color--spectral type and color--color relations of late typedwarfs in the SDSS filters, and to derive spectroscopic and photometricparallax relations for use in future studies of the luminosity and massfunctions based on SDSS data. We find that the (i*-z*) and (i*-J) colorsprovide good spectral type and absolute magnitude (M_i*) estimates for M and Ldwarfs. Our distance estimates for the current sample indicate that SDSS isfinding early M dwarfs out to about 1.5 kpc, L dwarfs to approximately 100 pcand T dwarfs to near 20 pc. The T dwarf photometric data show large scatter andare therefore less reliable for spectral type and distance estimation.Comment: 46 pages, 14 figures (24 pages of figures), Accepted for publication in the Astronomical Journa