Extended I-Love relations for slowly rotating neutron stars

Abstract

Observations of gravitational waves from inspiralling neutron star binaries---such as GW170817---can be used to constrain the nuclear equation of state by placing bounds on stellar tidal deformability. For slowly rotating neutron stars, the response to a weak quadrupolar tidal field is characterized by four internal-structure-dependent constants called "Love numbers." The tidal Love numbers $k_2^{\text{el}}$ and $k_2^{\text{mag}}$ measure the tides raised by the gravitoelectric and gravitomagnetic components of the applied field, and the rotational-tidal Love numbers ${\mathfrak{f}}^{\text{o}}$ and ${\mathfrak{k}}^{\text{o}}$ measure those raised by couplings between the applied field and the neutron star spin. In this work we compute these four Love numbers for perfect fluid neutron stars with realistic equations of state. We discover (nearly) equation-of-state independent relations between the rotational-tidal Love numbers and the moment of inertia, thereby extending the scope of I-Love-Q universality. We find that similar relations hold among the tidal and rotational-tidal Love numbers. These relations extend the applications of I-Love universality in gravitational-wave astronomy. As our findings differ from those reported in the literature, we derive general formulas for the rotational-tidal Love numbers in post-Newtonian theory and confirm numerically that they agree with our general-relativistic computations in the weak-field limit.

31 pages, 6 figures, 9 tables; v2: updated to match published version

References in corpus (16)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Shapiro delay measurement of a two solar mass neutron star
• A Massive Pulsar in a Compact Relativistic Binary
• Tidal Love numbers of neutron stars
• Constraining neutron star tidal Love numbers with gravitational wave detectors
• Constraints on a phenomenologically parameterized neutron-star equation of state
• Relativistic theory of tidal Love numbers
• Post-1-Newtonian tidal effects in the gravitational waveform from binary inspirals
• Analytic modelling of tidal effects in the relativistic inspiral of binary neutron stars
• Tidal deformation of a slowly rotating black hole
• Why I-Love-Q
• Gravitomagnetic response of an irrotational body to an applied tidal field
• Relativistic theory of surficial Love numbers
• A light-cone gauge for black-hole perturbation theory
• Gravitomagnetic tidal currents in rotating neutron stars
• I-Love-Q to the extreme

Cited by in corpus (21)

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• Tidal deformability of dressed black holes and tests of ultralight bosons in extended mass ranges
• Post-Newtonian spin-tidal couplings for compact binaries
• Constraining black hole mimickers with gravitational wave observations
• Can we distinguish low mass black holes in neutron star binaries?
• Impact of high-order tidal terms on binary neutron-star waveforms
• Magnetic tidal Love numbers clarified
• Gravitomagnetic tidal effects in gravitational waves from neutron star binaries
• Gravitomagnetic Love tensor of a slowly rotating body: post-Newtonian theory
• Relativistic effective action of dynamical gravitomagnetic tides for slowly rotating neutron stars
• Impact of updated Multipole Love numbers and f-Love Universal Relations in the context of Binary Neutron Stars
• Universal relations for compact stars with heavy baryons
• Universal relations for compact stars with exotic degrees of freedom
• Rotational-tidal phasing of the binary neutron star waveform
• Hidden symmetry between rotational tidal Love numbers of spinning neutron stars
• I-C-Q relations for rapidly rotating stable hybrid stars
• Tidal deformations of compact objects and gravitational wave emission
• Impact and detectability of spin-tidal couplings in neutron star inspirals
• Equation-of-State Independent Relations in Rapidly Rotating Hybrid Stars