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Constraining the magnetic field on white dwarf surfaces; Zeeman effects and fine structure constant variation

Authors :
Nicole Reindl
Chung-Chi Lee
Julian C. Berengut
John D. Barrow
Matthew Bainbridge
V. A. Dzuba
Jay B. Holberg
Thomas R. Ayres
Robert F. Carswell
Victor V. Flambaum
Jiting Hu
W. Ü. L. Tchang-Brillet
Martin A. Barstow
S. P. Preval
John K. Webb
Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112))
Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris
PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP)
Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Observatoire de Paris
Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)
Barrow, John [0000-0002-6083-9751]
Apollo - University of Cambridge Repository
Source :
Mon.Not.Roy.Astron.Soc., Mon.Not.Roy.Astron.Soc., 2019, 485 (4), pp.5050-5058. ⟨10.1093/mnras/stz739⟩
Publication Year :
2019
Publisher :
HAL CCSD, 2019.

Abstract

White dwarf atmospheres are subjected to gravitational potentials around $10^5$ times larger than occur on Earth. They provide a unique environment in which to search for any possible variation in fundamental physics in the presence of strong gravitational fields. However, a sufficiently strong magnetic field will alter absorption line profiles and introduce additional uncertainties in measurements of the fine structure constant. Estimating the magnetic field strength is thus essential in this context. Here we model the absorption profiles of a large number of atomic transitions in the white dwarf photosphere, including first-order Zeeman effects in the line profiles, varying the magnetic field as a free parameter. We apply the method to a high signal-to-noise, high-resolution, far-ultraviolet HST/STIS spectrum of the white dwarf G191-B2B. The method yields a sensitive upper limit on its magnetic field of $B < 2300$ Gauss at the $3\sigma$ level. Using this upper limit we find that the potential impact of quadratic Zeeman shifts on measurements of the fine structure constant in G191-B2B is 4 orders of magnitude below laboratory wavelength uncertainties.<br />Comment: 10 pages, 5 figures

Details

Language :
English
Database :
OpenAIRE
Journal :
Mon.Not.Roy.Astron.Soc., Mon.Not.Roy.Astron.Soc., 2019, 485 (4), pp.5050-5058. ⟨10.1093/mnras/stz739⟩
Accession number :
edsair.doi.dedup.....7e49f2ed64efefe901e98a506460bfae
Full Text :
https://doi.org/10.1093/mnras/stz739⟩