A Bayesian Approach to Deriving Ages of Individual Field White Dwarfs

TL;DR

This paper introduces a Bayesian method for accurately determining the ages, distances, and initial masses of field white dwarfs using photometry, revealing complex correlations and asymmetric age distributions.

Contribution

It presents a self-consistent Bayesian approach that improves age estimates of white dwarfs, accounting for complex correlations and asymmetries often overlooked by traditional methods.

Findings

Age estimates have less than 15% uncertainty.

Age, distance, and ZAMS mass are highly correlated.

Posterior age distributions are often asymmetric.

Abstract

We apply a self-consistent and robust Bayesian statistical approach to determining the ages, distances, and ZAMS masses of 28 field DA white dwarfs with ages of approximately 4 to 8 Gyrs. Our technique requires only quality optical and near-IR photometry to derive ages with < 15% uncertainties, generally with little sensitivity to our choice of modern initial-final mass relation. We find that age, distance, and ZAMS mass are correlated in a manner that is too complex to be captured by traditional error propagation techniques. We further find that the posterior distributions of age are often asymmetric, indicating that the standard approach to deriving WD ages can yield misleading results.