A Catalog of GALEX Ultraviolet Emission from Spectroscopically Confirmed M Dwarfs

TL;DR

This paper provides a catalog of ultraviolet measurements for spectroscopically confirmed M dwarfs, revealing correlations with magnetic activity, spectral type, and stellar age, and offering insights into M dwarf UV emission characteristics.

Contribution

It introduces a comprehensive UV photometry catalog for M dwarfs and analyzes their activity levels and dependence on spectral type and galactic position.

Findings

NUV and FUV luminosities correlate with Hα emission.

UV emission peaks at intermediate spectral types (~M4-M5).

UV activity decreases with distance from the Galactic plane.

Abstract

We present a catalog of GALEX Near-UV (NUV) and Far-UV (FUV) photometry for the Palomar/MSU and SDSS DR7 spectroscopic M dwarf catalogs. The catalog contains NUV measurements matched to 577 spectroscopically confirmed M dwarfs and FUV measurements matched to 150 spectroscopically confirmed M dwarfs. Using these data, we find that NUV and FUV luminosities strongly correlate with H{\alpha} emission, a typical indicator of magnetic activity in M dwarfs. We also examine the fraction of M dwarfs with varying degrees of strong line emission at NUV wavelengths. Our results indicate that the frequency of M dwarf NUV emission peaks at intermediate spectral types, with at least ~30% of young M4-M5 dwarfs having some level of activity. For mid-type M dwarfs, we show that NUV emission decreases with distance from the Galactic plane, a proxy for stellar age. Our complete matched source catalog is available online.