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Gravitational waves from non-radial oscillations of stochastically accreting neutron stars.
- Source :
- Monthly Notices of the Royal Astronomical Society; May2024, Vol. 530 Issue 3, p2822-2839, 18p
- Publication Year :
- 2024
-
Abstract
- Oscillating neutron stars are sources of continuous gravitational waves. We study analytically the excitation of stellar oscillations by the mechanical impact on the stellar surface of 'clumps' of stochastically accreted matter. We calculate the waveform and spectrum of the gravitational wave signal emitted by the accretion-driven pulsations. Results are generated for an idealized model of a non-rotating, unmagnetized, one-component star with uniform polytropic index n <subscript>poly</subscript> assuming Newtonian gravity and the Cowling approximation. We find that the excited mode amplitudes grow with increasing n <subscript>poly</subscript> and mode order n. The gravitational wave signal forms a sequence of amplitude-modulated packets for n <subscript>poly</subscript> = 1, lasting ∼10<superscript>−3</superscript> s after each impact. The gravitational wave strain increases with increasing n <subscript>poly</subscript>, but decreases with increasing n and increasing multipole order l for n <subscript>poly</subscript> = 1. In the observing band of current long-baseline interferometers, g modes emit higher, narrower peaks in the amplitude spectral density than f and p modes, with the highest peaks reaching ∼10<superscript>−26</superscript> Hz<superscript>−1/2</superscript> for modes with damping time τ<subscript> nl </subscript> ∼ 10<superscript>8</superscript> yr. The root-mean-square strain h <subscript>rms</subscript>, calculated by summing over modes with 2 ≤ l ≤ 4 and τ<subscript> nl </subscript> ≤ 10<superscript>8</superscript> yr, spans the range 10<superscript>−33</superscript> ≤ h <subscript>rms</subscript> ≤ 10<superscript>−32</superscript> for 1 ≤ n <subscript>poly</subscript> ≤ 2. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 530
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 177106875
- Full Text :
- https://doi.org/10.1093/mnras/stae1028