DA white dwarfs observed in LAMOST pilot survey

TL;DR

This paper presents a catalog of 230 DA white dwarfs from the LAMOST pilot survey, using a new spectral fitting algorithm to identify candidates and confirm their classification.

Contribution

The study introduces a novel spectral fitting method for white dwarf selection and provides a comprehensive catalog from the LAMOST pilot survey.

Findings

Identified 230 DA white dwarfs, including some with companions.

The catalog is consistent with expected white dwarf numbers.

A new algorithm effectively selects white dwarf candidates.

Abstract

A total of $\sim640,000$ objects from LAMOST pilot survey have been publicly released. In this work, we present a catalog of DA white dwarfs from the entire pilot survey. We outline a new algorithm for the selection of white dwarfs by fitting S\'ersic profiles to the Balmer H$\beta$, H$\gamma$ and H$\delta$ lines of the spectra, and calculating the equivalent width of the CaII K line. 2964 candidates are selected by constraining the fitting parameters and the equivalent width of CaII K line. All the spectra of candidates are visually inspected. We identify 230 (59 of them are already in Villanova and SDSS WD catalog) DA white dwarfs, 20 of which are DA white dwarfs with non-degenerate companions. In addition, 128 candidates are classified as DA white dwarf/subdwarfs, which means the classifications are ambiguous. The result is consistent with the expected DA white dwarf number estimated based on the LEGUE target selection algorithm.