### Abstract

Original language | English |
---|---|

Article number | 061104 |

Pages (from-to) | 1-13 |

Number of pages | 13 |

Journal | Physical Review Letters |

Volume | 122 |

Issue number | 6 |

DOIs | |

Publication status | Published - 13 Feb 2019 |

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### Cite this

**-Mode–**

*p**-Mode Tidal Instability with GW170817.*

**g***Physical Review Letters*,

*122*(6), 1-13. [061104]. https://doi.org/10.1103/PhysRevLett.122.061104

}

**-Mode–**

*p**-Mode Tidal Instability with GW170817',*

**g***Physical Review Letters*, vol. 122, no. 6, 061104, pp. 1-13. https://doi.org/10.1103/PhysRevLett.122.061104

**Constraining the p-Mode–g-Mode Tidal Instability with GW170817.** / Charlton, Philip.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Constraining the p-Mode–g-Mode Tidal Instability with GW170817

AU - Charlton, Philip

PY - 2019/2/13

Y1 - 2019/2/13

N2 - 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 (lnBpg!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 lnBpg!pg=0.03+0.70−0.58 (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 lnBpg!pg even when p−g effects are absent. We find that the p−g amplitude for 1.4 M⊙ neutron 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 ≲103 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 ≲1051 erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

AB - 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 (lnBpg!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 lnBpg!pg=0.03+0.70−0.58 (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 lnBpg!pg even when p−g effects are absent. We find that the p−g amplitude for 1.4 M⊙ neutron 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 ≲103 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 ≲1051 erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

KW - Gravitational wave detection

KW - gravitational wave sources

KW - gravitational waves

U2 - 10.1103/PhysRevLett.122.061104

DO - 10.1103/PhysRevLett.122.061104

M3 - Article

C2 - 30822067

VL - 122

SP - 1

EP - 13

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 6

M1 - 061104

ER -

**-Mode–**

*p**-Mode Tidal Instability with GW170817. Physical Review Letters. 2019 Feb 13;122(6):1-13. 061104. https://doi.org/10.1103/PhysRevLett.122.061104*

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