Statistical properties of the GALEX spectroscopic stellar sample

TL;DR

This paper analyzes the statistical properties of over 60,000 ultraviolet stellar spectra from GALEX, defining indices to determine stellar parameters and revealing a majority of F- and G-type main sequence stars with moderate metallicity.

Contribution

It introduces a system of spectroscopic indices for low-resolution UV spectra and applies it to characterize the stellar sample from GALEX data.

Findings

Majority of stars are main sequence F- and G-type.

Sample has metallicity [M/H]>-1 dex.

Method enables atmospheric parameter estimation from UV spectra.

Abstract

The GALEX General Data Release 4/5 includes 174 spectroscopic tiles, obtained from slitless grism observations, for a total of more than 60,000 ultraviolet spectra. We have determined statistical properties of the sample of GALEX stars. We have defined a suitable system of spectroscopic indices, which measure the main mid-UV features at the GALEX low spectral resolution and we have employed it to determine the atmospheric parameters of of stars in the range 4500<Teff<9000 K. Our preliminary results indicate that the sample is formed by a majority of main sequence F- and G-type stars, with metallicity [M/H]>-1 dex.