BibTeX

@article{2503.11875v1,
Author        = {Mattéo Sautron and Alexander Eli McEwen and George Younes and Jérôme Pétri and Paz Beniamini and Daniela Huppenkothen},
Title         = {The Galactic population of magnetars : a simulation-based inference
  study},
Eprint        = {2503.11875v1},
DOI           = {10.3847/1538-4357/add0aa},
ArchivePrefix = {arXiv},
PrimaryClass  = {astro-ph.HE},
Abstract      = {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 which 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 $\sim$30 known magnetars are discovered
through their bursting activity in the last $\sim50$ years. Under these
constraints, we find that, within 95 % credible intervals, the birth rate of
magnetars to be $1.8^{+2.6}_{-0.6}$ kyr$^{-1}$, and lead to having
$10.7^{+18.8}_{-4.4}$ % of neutron stars born as magnetars. We also find a mean
magnetic field at birth ($\mu_b$ is in T) $\log\left(\mu_b\right) =
10.2^{+0.1}_{-0.2}$, a magnetic field decay slope $\alpha_d = 1.9
^{+0.9}_{-1.3}$, and timescale $\tau_d = 17.9^{+24.1}_{-14.5}$ 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
to get around 7 periodic detections of magnetars, with approximately 150
magnetars exceeding XMM-Newton's flux threshold, and the upcoming AXIS
experiment should allow to double these detections.},
Year          = {2025},
Month         = {Mar},
Note          = {Astrophys. J. 986, 88 (2025)},
Url           = {http://arxiv.org/abs/2503.11875v1},
File          = {2503.11875v1.pdf}
}