A new sample of nearby M dwarfs discovered by ROSAT

I am using the ROSAT All-Sky Survey to identify M dwarfs within 25 pc of the Sun that are missing from the Catalogue of Nearby Stars. Selection by X-rays is very efficient for this purpose since the stars found will tend to be young and, hence, have small space motions. It is just such stars that are missing from the Catalogue of Nearby Stars, which largely consists of stars first discovered in proper-motion surveys. In this paper, I present an initial list of 54 M dwarfs, which, by virtue of their photometric parallaxes, should be included in the Catalogue. These preliminary results are also used to estimate that, because of this effect, the amount of mass that is missing from estimates of the local Galactic mass density is 0.003 M. pc(-3). This amount is insufficient to solve the Galactic "missing mass" problem.