A hierarchical model for the ages of Galactic halo white dwarfs
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Published version
Author(s)
Type
Journal Article
Abstract
In astrophysics, we often aim to estimate one or more parameters for each member object in a population and study the distribution of the fitted parameters across the population. In this paper, we develop novel methods that allow us to take advantage of existing software designed for such case-by-case analyses to simultaneously fit parameters of both the individual objects and the parameters that quantify their distribution across the population. Our methods are based on Bayesian hierarchical modelling that is known to produce parameter estimators for the individual objects that are on average closer to their true values than estimators based on case-by-case analyses. We verify this in the context of estimating ages of Galactic halo white dwarfs (WDs) via a series of simulation studies. Finally, we deploy our new techniques on optical and near-infrared photometry of 10 candidate halo WDs to obtain estimates of their ages along with an estimate of the mean age of Galactic halo WDs of 12.11+0.85−0.86 Gyr. Although this sample is small, our technique lays the ground work for large-scale studies using data from the Gaia mission.
Date Issued
2017-03-29
Date Acceptance
2017-03-29
ISSN
1365-2966
Publisher
Oxford University Press (OUP)
Start Page
4374
End Page
4388
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
468
Issue
4
Copyright Statement
© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. This article has been accepted for publication in MNRAS.
Sponsor
Commission of the European Communities
Commission of the European Communities
Grant Number
691164
FP7-PEOPLE-2012-CIG-321865
Subjects
Astronomy & Astrophysics
0201 Astronomical And Space Sciences
Publication Status
Published