Population synthesis of accreting neutron stars emitting gravitational waves
Population synthesis of accreting neutron stars emitting gravitational waves
The fastest-spinning neutron stars in low-mass X-ray binaries, despite having undergone millions of years of accretion, have been observed to spin well below the Keplerian break-up frequency. We simulate the spin evolution of synthetic populations of accreting neutron stars in order to assess whether gravitational waves can explain this behaviour and provide the distribution of spins that is observed. We model both persistent and transient accretion and consider two gravitational-wave-production mechanisms that could be present in these systems: thermal mountains and unstable rmodes. We consider the case of no gravitational-wave emission and observe that this does not match well with observation. We find evidence for gravitational waves being able to provide the observed spin distribution; the most promising mechanisms being a permanent quadrupole, thermal mountains, and unstable r modes. However, based on the resultant distributions alone, it is difficult to distinguish between the competing mechanisms.
99-110
Gittins, Fabian
657ec875-fac3-4606-9dcd-591ef22fc9f6
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
1 September 2019
Gittins, Fabian
657ec875-fac3-4606-9dcd-591ef22fc9f6
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Gittins, Fabian and Andersson, Nils
(2019)
Population synthesis of accreting neutron stars emitting gravitational waves.
Monthly Notices of the Royal Astronomical Society, 488 (1), .
(doi:10.1093/mnras/stz1719).
Abstract
The fastest-spinning neutron stars in low-mass X-ray binaries, despite having undergone millions of years of accretion, have been observed to spin well below the Keplerian break-up frequency. We simulate the spin evolution of synthetic populations of accreting neutron stars in order to assess whether gravitational waves can explain this behaviour and provide the distribution of spins that is observed. We model both persistent and transient accretion and consider two gravitational-wave-production mechanisms that could be present in these systems: thermal mountains and unstable rmodes. We consider the case of no gravitational-wave emission and observe that this does not match well with observation. We find evidence for gravitational waves being able to provide the observed spin distribution; the most promising mechanisms being a permanent quadrupole, thermal mountains, and unstable r modes. However, based on the resultant distributions alone, it is difficult to distinguish between the competing mechanisms.
Text
1811.00550
- Accepted Manuscript
Available under License Other.
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Accepted/In Press date: 18 June 2019
e-pub ahead of print date: 21 June 2019
Published date: 1 September 2019
Identifiers
Local EPrints ID: 434784
URI: http://eprints.soton.ac.uk/id/eprint/434784
ISSN: 1365-2966
PURE UUID: d00fc741-f909-4c41-9c15-73eaeccadca8
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Date deposited: 09 Oct 2019 16:30
Last modified: 17 Mar 2024 02:47
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Author:
Fabian Gittins
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