The Solar Neighborhood. XXXV. Distances to 1404 m Dwarf Systems Within 25 pc in the Southern Sky

We present trigonometric, photometric, and photographic distances to 1748 southern (δ ≤slant 0{}^\circ ) M dwarf systems with μ ≥slant 0_\cdot ^{{\prime\prime} }18 yr^-1, of which 1404 are believed to lie within 25 pc of the Sun. The stars have 6.67≤slant {{V}_J}≤slant 21.38 and 3.50≤slant ({{V}_J}-{{K}_s})≤slant 9.27, covering the entire M dwarf spectral sequence from M0.0 V through M9.5 V. This sample therefore provides a comprehensive snapshot of our current knowledge of the southern sky for the nearest M dwarfs that dominate the stellar population of the Galaxy. Roughly one-third of the 1748 systems, each of which has an M dwarf primary, have published high quality parallaxes, including 179 from the REsearch Consortium On Nearby Stars astrometry program. For the remaining systems, we offer photometric distance estimates that have well-calibrated errors. The bulk of these (̃700) are based on new {{V}_J}{{R}_KC}{{I}_KC} photometry acquired at the CTIO/SMARTS 0.9 m telescope, while the remaining 500 primaries have photographic plate distance estimates calculated using SuperCOSMOS {{B}_J}{{R}_59F}{{I}_IVN} photometry. Confirmed and candidate subdwarfs in the sample have been identified, and a census of companions is included.