Constraining the p-Mode–g-Mode Tidal Instability with GW170817
Name
PhysRevLett.122.061104.pdf
Size
1.16 MB
Format
Adobe PDF
Checksum (MD5)
3c43c2a922f3552f6a3c699fc2e89b0f
Date Issued
February 2019
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Abbott, B. P. et al. “Constraining the p-Mode–g-Mode Tidal Instability with GW170817.” Physical Review Letters 122, 6 (February 2019): 061104. © 2019 American Physical Society.
Version
Final published version
Abstract
We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: An overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (ln B[subscript !pg][superscript pg]) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with ln B[subscript !pg][superscript pg]=0.03[subscript -0.58][superscript +0.70] (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar ln B[subscript !pg][superscript pg] even when p-g effects are absent. We find that the p-g amplitude for 1.4 M[⊙] stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-Tenth this maximum and p-g saturation frequency ∼70 Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest a 10[superscript 3] modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲ 10[superscript 51] erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.
MIT Department
Massachusetts Institute of Technology. Department of Physics
LIGO (Observatory : Massachusetts Institute of Technology)
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.122.061104
