THE SLOAN DIGITAL SKY SURVEY DATA RELEASE 7 SPECTROSCOPIC M DWARF CATALOG. I. DATA

Abstract

We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from\nthe seventh data release of the Sloan Digital Sky Survey (SDSS). For each\nspectrum, we provide measurements of the spectral type, a number of molecular\nbandheads, and the H-alpha, H-beta, H-gamma, H-delta and Ca II K emission\nlines. In addition, we calculate the metallicity-sensitive parameter zeta and\nidentify a relationship between zeta and the g-r and r-z colors of M dwarfs. We\nassess the precision of our spectral types (which were assigned by individual\nexamination), review the bulk attributes of the sample, and examine the\nmagnetic activity properties of M dwarfs, in particular those traced by the\nhigher order Balmer transitions. Our catalog is cross-matched to Two Micron All\nSky Survey (2MASS) infrared data, and contains photometric distances for each\nstar. Lastly, we identify eight new late-type M dwarfs that are possibly within\n25 pc of the Sun. Future studies will use these data to thoroughly examine\nmagnetic activity and kinematics in late-type M dwarfs and examine the chemical\nand dynamical history of the local Milky Way.\n