Spectrophotometric analysis of magnetic white dwarf I: Hydrogen-rich compositions

TL;DR

This study provides a comprehensive spectrophotometric analysis of magnetic hydrogen-rich white dwarfs, refining their atmospheric parameters and magnetic field properties to better understand their origins and evolution.

Contribution

It offers a homogeneous reanalysis of known magnetic white dwarfs with improved models, clarifying their classification and magnetic characteristics.

Findings

Refined atmospheric parameters for magnetic white dwarfs.

Reclassification of several objects from potential to confirmed magnetic.

Insights into the distribution and evolution of magnetic fields in white dwarfs.

Abstract

We present an homogeneous analysis of all DA stars labeled as magnetic in the Montreal White Dwarf Database (MWDD). Our sample is restricted to almost all known magnetic white dwarf showing clear sign of splitting ($B \gtrsim$ 1-2 MG) that have parallax measurements from the second Gaia data release, photometric data from diverse surveys and spectroscopic data from SDSS or archival data from the Montreal group. We determine the atmospheric parameters (effective temperature, surface gravity, magnetic field strength/geometry) of all objects using state-of-the-art model atmosphere/magnetic synthetic spectra, as well as reclassify many objects that were prematurely labeled as potentially magnetic. Finally, we discuss the atmospheric parameters/field properties distribution as well as the implication on our understanding of magnetic white dwarfs origin and evolution.