Transient discs around isolated accreting neutron stars
Abstract
Mature, isolated neutron stars can accrete from the interstellar medium. Due to turbulence, the accreted gas can have a substantial angular momentum and form a disc around the compact object. In this paper, we perform a population synthesis of isolated neutron stars in the Milky Way that specifically tracks the possibility of disc formation, which typically requires a low spatial velocity of the compact object (≲ 40 km s−1). In general, weak magnetic fields favour disc formation as the magnetosphere occupies a smaller volume. Still, even in the case of fields decaying exponentially over a characteristic timescale of ∼ 1.5 Gyr, we find that for several realistic models of propeller spin-down, only a small fraction of accretors (down to ∼ 0.02 %) attain discs. However, disc-accreting isolated neutron stars are relatively numerous among the brightest sources. We estimate that their number can reach a few hundred at X-ray fluxes of ≳ 10−14 erg s−1 cm−2. We speculate that disc-accreting isolated neutron stars can manifest as long-period radio transient sources via electron cyclotron maser emission, predicting spectra and critical conditions for quenching.
Related
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BibTeX
@misc{afonina2026transient,
title = {{Transient discs around isolated accreting neutron stars}},
author = {Marina D. Afonina and Anton V. Biryukov and Sergei B. Popov and Arthur G. Suvorov},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.02442},
eprint = {2609.02442},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.02442},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Transient discs around isolated accreting neutron stars
AU - Marina D. Afonina
AU - Anton V. Biryukov
AU - Sergei B. Popov
AU - Arthur G. Suvorov
PY - 2026
DA - 2026/09/02
PB - arXiv
DO - 10.48550/arxiv.2609.02442
UR - https://arxiv.org/abs/2609.02442
AB - Mature, isolated neutron stars can accrete from the interstellar medium. Due to turbulence, the accreted gas can have a substantial angular momentum and form a disc around the compact object. In this paper, we perform a population synthesis of isolated neutron stars in the Milky Way that specifically tracks the possibility of disc formation, which typically requires a low spatial velocity of the compact object (≲ 40 km s^−1). In general, weak magnetic fields favour disc formation as the magnetosphere occupies a smaller volume. Still, even in the case of fields decaying exponentially over a characteristic timescale of ∼ 1.5 Gyr, we find that for several realistic models of propeller spin-down, only a small fraction of accretors (down to ∼ 0.02 %) attain discs. However, disc-accreting isolated neutron stars are relatively numerous among the brightest sources. We estimate that their number can reach a few hundred at X-ray fluxes of ≳ 10^−14 erg s^−1 cm^−2. We speculate that disc-accreting isolated neutron stars can manifest as long-period radio transient sources via electron cyclotron maser emission, predicting spectra and critical conditions for quenching.
ER -