The Galactic Population of Magnetars: A Simulation-based Inference Study

Population synthesis modeling of the observed dynamical and physical properties of a population is a highly effective method for constraining the underlying birth parameters and evolutionary tracks. In this work, we apply a population synthesis model to the canonical magnetar population to gain insi...

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Main Authors: M. Sautron, A. E. McEwen, G. Younes, J. Pétri, P. Beniamini, D. Huppenkothen
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/add0aa
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author M. Sautron
A. E. McEwen
G. Younes
J. Pétri
P. Beniamini
D. Huppenkothen
author_facet M. Sautron
A. E. McEwen
G. Younes
J. Pétri
P. Beniamini
D. Huppenkothen
author_sort M. Sautron
collection DOAJ
description Population synthesis modeling of the observed dynamical and physical properties of a population is a highly effective method for constraining the underlying birth parameters and evolutionary tracks. In this work, we apply a population synthesis model to the canonical magnetar population to gain insight into the parent population. We utilize simulation-based inference to reproduce the observed magnetar population with a model that takes into account the secular evolution of the force-free magnetosphere and magnetic field decay simultaneously and self-consistently. Our observational constraints are such that no magnetar is detected through their persistent emission when convolving the simulated populations with the XMM-Newton EPIC-pn Galactic plane observations, and that all of the ∼30 known magnetars are discovered through their bursting activity in the last ∼50 yr. Under these constraints, we find, within 95% credible intervals, the birth rate of magnetars to be $1.{8}_{-0.6}^{+2.6}$ kyr ^−1 , leading to having $10.{7}_{-4.4}^{+18.8}$ % of neutron stars born as magnetars. We also find a mean magnetic field at birth ( μ _b is in T) ${\mathrm{log}}\,\left({\mu }_{b}\right)=10.{2}_{-0.2}^{+0.1}$ , a magnetic field decay slope ${\alpha }_{d}=1.{9}_{-1.3}^{+0.9}$ , and timescale ${\tau }_{d}=17.{9}_{-14.5}^{+24.1}$ kyr, in broad agreement with previous estimates. We conclude this study by exploring detection prospects: an all-sky survey with XMM-Newton would potentially allow around seven periodic detections of magnetars to be obtained, with approximately 150 magnetars exceeding XMM-Newton’s flux threshold, and the upcoming AXIS experiment should allow these detections to be doubled.
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spelling doaj-art-ac4ee447f5a94e98ba53435e7fea4ec32025-08-20T02:35:26ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198618810.3847/1538-4357/add0aaThe Galactic Population of Magnetars: A Simulation-based Inference StudyM. Sautron0https://orcid.org/0009-0006-7913-1186A. E. McEwen1https://orcid.org/0000-0001-5481-7559G. Younes2https://orcid.org/0000-0002-7991-028XJ. Pétri3https://orcid.org/0000-0003-3790-8066P. Beniamini4https://orcid.org/0000-0001-7833-1043D. Huppenkothen5https://orcid.org/0000-0002-1169-7486Université de Strasbourg , CNRS, Observatoire astronomique de Strasbourg, UMR 7550, 67000 Strasbourg, France ; matteo.sautron@gmail.comCenter for Space Sciences and Technology, University of Maryland , Baltimore County, Baltimore, MD 21250, USA ; almcewen0@hotmail.comCenter for Space Sciences and Technology, University of Maryland , Baltimore County, Baltimore, MD 21250, USA ; almcewen0@hotmail.com; Astrophysics Science Division , NASA/GSFC, Greenbelt, MD 20771, USAUniversité de Strasbourg , CNRS, Observatoire astronomique de Strasbourg, UMR 7550, 67000 Strasbourg, France ; matteo.sautron@gmail.comDepartment of Physics, T he George Washington University , Washington, DC 20052, USA; Department of Natural Sciences, The Open University of Israel , P.O. Box 808, Ra’anana 4353701, Israel; Astrophysics Research Center of the Open University (ARCO) , The Open University of Israel, P.O. Box 808, Ra’anana 4353701, IsraelAnton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, 1098XH Amsterdam, The NetherlandsPopulation synthesis modeling of the observed dynamical and physical properties of a population is a highly effective method for constraining the underlying birth parameters and evolutionary tracks. In this work, we apply a population synthesis model to the canonical magnetar population to gain insight into the parent population. We utilize simulation-based inference to reproduce the observed magnetar population with a model that takes into account the secular evolution of the force-free magnetosphere and magnetic field decay simultaneously and self-consistently. Our observational constraints are such that no magnetar is detected through their persistent emission when convolving the simulated populations with the XMM-Newton EPIC-pn Galactic plane observations, and that all of the ∼30 known magnetars are discovered through their bursting activity in the last ∼50 yr. Under these constraints, we find, within 95% credible intervals, the birth rate of magnetars to be $1.{8}_{-0.6}^{+2.6}$ kyr ^−1 , leading to having $10.{7}_{-4.4}^{+18.8}$ % of neutron stars born as magnetars. We also find a mean magnetic field at birth ( μ _b is in T) ${\mathrm{log}}\,\left({\mu }_{b}\right)=10.{2}_{-0.2}^{+0.1}$ , a magnetic field decay slope ${\alpha }_{d}=1.{9}_{-1.3}^{+0.9}$ , and timescale ${\tau }_{d}=17.{9}_{-14.5}^{+24.1}$ kyr, in broad agreement with previous estimates. We conclude this study by exploring detection prospects: an all-sky survey with XMM-Newton would potentially allow around seven periodic detections of magnetars to be obtained, with approximately 150 magnetars exceeding XMM-Newton’s flux threshold, and the upcoming AXIS experiment should allow these detections to be doubled.https://doi.org/10.3847/1538-4357/add0aaMagnetarsX-ray burstsX-ray sources
spellingShingle M. Sautron
A. E. McEwen
G. Younes
J. Pétri
P. Beniamini
D. Huppenkothen
The Galactic Population of Magnetars: A Simulation-based Inference Study
The Astrophysical Journal
Magnetars
X-ray bursts
X-ray sources
title The Galactic Population of Magnetars: A Simulation-based Inference Study
title_full The Galactic Population of Magnetars: A Simulation-based Inference Study
title_fullStr The Galactic Population of Magnetars: A Simulation-based Inference Study
title_full_unstemmed The Galactic Population of Magnetars: A Simulation-based Inference Study
title_short The Galactic Population of Magnetars: A Simulation-based Inference Study
title_sort galactic population of magnetars a simulation based inference study
topic Magnetars
X-ray bursts
X-ray sources
url https://doi.org/10.3847/1538-4357/add0aa
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