An Equilibrium Model of the Galaxy Determined by Element Abundance Gradients

We present a method to determine the gravitational potential of the Milky Way from measurements of the locations, velocities, and element abundances of stars in the Galactic disk. The method relies on the assumption that the Galaxy is axisymmetric and stationary and that element abundance ratios suc...

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Main Authors: Lawrence M. Widrow, David W. Hogg, Danny Horta, Haochaun Li, Adrian M. Price-Whelan
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adbf12
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author Lawrence M. Widrow
David W. Hogg
Danny Horta
Haochaun Li
Adrian M. Price-Whelan
author_facet Lawrence M. Widrow
David W. Hogg
Danny Horta
Haochaun Li
Adrian M. Price-Whelan
author_sort Lawrence M. Widrow
collection DOAJ
description We present a method to determine the gravitational potential of the Milky Way from measurements of the locations, velocities, and element abundances of stars in the Galactic disk. The method relies on the assumption that the Galaxy is axisymmetric and stationary and that element abundance ratios such as [Fe/H] and [Mg/Fe] are smooth functions of three isolating integrals of motion. We use Fisher Information theory to predict the efficacy of individual abundance ratios to constrain the potential. We also use N -body simulations to test the extent by which secular evolution in the disk introduces statistical and systematic errors into the analysis. We apply our method to a sample of stars from Gaia Data Release 3 and the APOGEE survey and infer the vertical force profile at the position of the Sun and the rotation curve in the midplane and find good agreement with previously published results. The residuals of the model show corrugations in [Fe/H] as a function of L _z , the angular momentum component along the spin axis of the Galaxy. Using the correspondence between L _z and Galactocentric cylindrical radius, we show that these features line up with the four spiral arms closest to the Sun.
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spelling doaj-art-a0ce9b83ee554ea1bb3af63a5783e95c2025-08-20T02:16:10ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01983213410.3847/1538-4357/adbf12An Equilibrium Model of the Galaxy Determined by Element Abundance GradientsLawrence M. Widrow0https://orcid.org/0000-0001-6211-8635David W. Hogg1https://orcid.org/0000-0003-2866-9403Danny Horta2https://orcid.org/0000-0003-1856-2151Haochaun Li3https://orcid.org/0000-0001-6538-9481Adrian M. Price-Whelan4https://orcid.org/0000-0003-0872-7098Department of Physics, Engineering Physics and Astronomy, Queen’s University , Kingston, Ontario, K7L 3N6, Canada ; widrow@queensu.caCenter for Computational Astrophysics, Flatiron Institute , 162 Fifth Avenue, New York, NY 10010, USA ; dhogg@flatironinstitute.org, dhortadarrington@flatironinstitute.org, aprice-whelan@flatironinstitute.org; Center for Cosmology and Particle Physics , Department of Physics, New York University, 726 Broadway, New York, NY 10003, USA; Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117 Heidelberg, GermanyCenter for Computational Astrophysics, Flatiron Institute , 162 Fifth Avenue, New York, NY 10010, USA ; dhogg@flatironinstitute.org, dhortadarrington@flatironinstitute.org, aprice-whelan@flatironinstitute.orgSchool of Physics and Astronomy, Shanghai Jiao Tong University , 800 Dong Chuan Road, Minhang District, Shanghai, 200240, People’s Republic of China ; haochuan.li@sjtu.edu.cnCenter for Computational Astrophysics, Flatiron Institute , 162 Fifth Avenue, New York, NY 10010, USA ; dhogg@flatironinstitute.org, dhortadarrington@flatironinstitute.org, aprice-whelan@flatironinstitute.orgWe present a method to determine the gravitational potential of the Milky Way from measurements of the locations, velocities, and element abundances of stars in the Galactic disk. The method relies on the assumption that the Galaxy is axisymmetric and stationary and that element abundance ratios such as [Fe/H] and [Mg/Fe] are smooth functions of three isolating integrals of motion. We use Fisher Information theory to predict the efficacy of individual abundance ratios to constrain the potential. We also use N -body simulations to test the extent by which secular evolution in the disk introduces statistical and systematic errors into the analysis. We apply our method to a sample of stars from Gaia Data Release 3 and the APOGEE survey and infer the vertical force profile at the position of the Sun and the rotation curve in the midplane and find good agreement with previously published results. The residuals of the model show corrugations in [Fe/H] as a function of L _z , the angular momentum component along the spin axis of the Galaxy. Using the correspondence between L _z and Galactocentric cylindrical radius, we show that these features line up with the four spiral arms closest to the Sun.https://doi.org/10.3847/1538-4357/adbf12Galaxy abundancesGalaxy kinematicsGalaxy structure
spellingShingle Lawrence M. Widrow
David W. Hogg
Danny Horta
Haochaun Li
Adrian M. Price-Whelan
An Equilibrium Model of the Galaxy Determined by Element Abundance Gradients
The Astrophysical Journal
Galaxy abundances
Galaxy kinematics
Galaxy structure
title An Equilibrium Model of the Galaxy Determined by Element Abundance Gradients
title_full An Equilibrium Model of the Galaxy Determined by Element Abundance Gradients
title_fullStr An Equilibrium Model of the Galaxy Determined by Element Abundance Gradients
title_full_unstemmed An Equilibrium Model of the Galaxy Determined by Element Abundance Gradients
title_short An Equilibrium Model of the Galaxy Determined by Element Abundance Gradients
title_sort equilibrium model of the galaxy determined by element abundance gradients
topic Galaxy abundances
Galaxy kinematics
Galaxy structure
url https://doi.org/10.3847/1538-4357/adbf12
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