We have identified 109 white dwarf (WD)-M dwarf pairs in the Sloan Digital Sky Survey (SDSS) with g<20th magnitude. For each system we determined the temperature of the WD primary and the spectral type of the M dwarf secondary. Using H{alpha} emission as a proxy for the chromospheric activity level of the M dwarf, we investigated correlations between the activity level and properties of the system. Compared with field M dwarfs previously observed in the Palomar/MSU Survey, we see a slightly higher active fraction of early-type stars, with activity levels similar to the field. We have conducted follow-up observations at the ARC 3.5m telescope to obtain radial velocity information and to search for short-period binaries that may be on the verge of interacting. We report on one system with a 4.1hr period and several additional systems with significant velocity variations.

Cone search capability for table J/AJ/125/2621/table1 (WD-M binary parameters)