SDSS DR7 White Dwarf Catalog

TL;DR

This paper presents an expanded catalog of over 19,700 spectroscopically confirmed white dwarf stars from SDSS DR7, including detailed classifications and atmospheric model fits, significantly increasing the known sample size.

Contribution

The paper provides a more comprehensive and conservatively classified white dwarf catalog from SDSS DR7, including magnetic white dwarfs and improved subtype distinctions.

Findings

Over 20,000 white dwarf spectra identified

DB white dwarf mean mass is larger than DA

Large number of magnetic white dwarfs discovered

Abstract

We present a new catalog of spectroscopically-confirmed white dwarf stars from the Sloan Digital Sky Survey Data Release 7 spectroscopic catalog. We find 20,407 white dwarf spectra, representing 19,712 stars, and provide atmospheric model fits to 14,120 DA and 1011 DB white dwarf spectra from 12,843 and 923 stars, respectively. These numbers represent a more than factor of two increase in the total number of white dwarf stars from the previous SDSS white dwarf catalog based on DR4 data. Our distribution of subtypes varies from previous catalogs due to our more conservative, manual classifications of each star in our catalog, supplementing our automatic fits. In particular, we find a large number of magnetic white dwarf stars whose small Zeeman splittings mimic increased Stark broadening that would otherwise result in an overestimated log(g) if fit as a non-magnetic white dwarf. We calculate mean DA and DB masses for our clean, non-magnetic sample and find the DB mean mass is statistically larger than that for the DAs.