72 DA White Dwarfs Identified in LAMOST Pilot Survey

TL;DR

This paper presents a catalog of 72 spectroscopically identified DA white dwarfs from the LAMOST pilot survey, including 35 new discoveries, with analysis of their physical properties and spatial distribution in the Galaxy.

Contribution

The study provides the first large spectroscopic catalog of DA white dwarfs from LAMOST, including new identifications and detailed physical parameter estimations.

Findings

Most white dwarfs are hot with a peak mass of ~0.6 M_sun.

White dwarfs with higher mass are concentrated near the Galactic plane.

All identified white dwarfs are part of the Galactic disk.

Abstract

We present a spectroscopically identified catalogue of 72 DA white dwarfs from the LAMOST pilot survey. 35 are found to be new identifications after cross-correlation with the Eisenstein et al. and Villanova catalogues. The effective temperature and gravity of these white dwarfs are estimated by Balmer lines fitting. Most of them are hot white dwarfs. The cooling times and masses of these white dwarfs are estimated by interpolation in theoretical evolution tracks. The peak of mass distribution is found to be $\sim$ 0.6 $M_\odot$ which is consistent with prior work in the literature. The distances of these white dwarfs are estimated using the method of Synthetic Spectral Distances. All of these WDs are found to be in the Galactic disk from our analysis of space motions. Our sample supports the expectation white dwarfs with high mass are concentrated near the plane of Galactic disk