Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2509.24461

Accounting for Tidal Deformability in Binary Neutron Star Template Banks

Lorenzo Piccari·Francesco Pannarale
View original source ↗Read source document ↗Export metadata ↓

Abstract

Modelled searches for gravitational waves emitted by compact binary coalescences currently filter the data with template signals that ignore all effects related to the physics of dense-matter in neutron stars interiors, even when the masses in the template are compatible with a binary neutron star or a neutron star-black hole binary source. The leading neutron star finite-size effect is an additional phase contribution due to tidal deformations induced by the gravitational coupling between the two inspiralling objects in the binary. We show how neglecting this effect in the templates reduces the search sensitivity close to the detection threshold. This is particularly true for binary neutron stars systems, where tidal effects are larger. In this work we therefore propose a new technique for the construction of binary neutron star template banks that accounts for neutron star tidal deformabilities as degrees of freedom of the parameter space to be searched over. A first attempt in this direction was carried out by Harry & Lundgren [Physical Review D 104, 043008 (2021)], who proposed to extract randomly the tidal deformabilities of the stars over a uniform interval, regardless of the binary neutron star component masses. We show that this approach yields 33% additional templates with respect to the equivalent point-like template bank. Our proposed approach, instead, adopts a more physically motivated tidal deformability prior with a support that is informed by the value of the neutron star mass and compatible with the neutron star equation of state constraint provided by the observation of GW170817. This method significantly reduces the needed additional templates to 8.2%.

Explore related subjects

gr-qcastro-ph.HE

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Lorenzo Piccari, Francesco Pannarale. 2025-09-29. Accounting for Tidal Deformability in Binary Neutron Star Template Banks. https://arxiv.org/abs/2509.24461

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Complex frequency evolution of direct waves from binary black hole mergers

While no signal originating at a black hole's event horizon can reach future null infinity, information about the horizon and its immediate vicinity can be encoded in asymptotic properties of waves emitted by matter or field perturbations falling toward a growing/forming horizon. Within a response-filtered framework, "direct wave" denotes source-sensitive plunge and remnant-formation information revealed by filtering the black-hole response. Unlike a stationary damped sinusoid with a fixed complex frequency, the direct wave follows the evolving source and has an evolving instantaneous complex frequency tied at late times to the remnant horizon angular velocity $Ω_H$ and surface gravity $κ_H$. Using rational filters, we remove quasinormal modes from numerical-relativity waveforms to study this evolution. Before numerical contamination, trajectories depend on remnant spin: the real frequency evolves toward $2Ω_H$ from above for lower spins ($χ_f\lesssim0.7$) and from below for higher spins ($χ_f\gtrsim0.7$), while the instantaneous decay rate increases, with best-resolved cases approaching the expected value of $3κ_H$. As in particle-plunge results, the horizon-controlled value is approached only at late times, as frame dragging controls near-horizon motion. For $χ_f\sim0.7$ remnants of non-precessing, comparable-mass binaries, the early-time real frequency is close to $2Ω_H$ because the binary orbital frequency transitions smoothly to the remnant horizon frequency. Finite-time deviations therefore carry information about merger/collapse dynamics rather than undermining the horizon connection. Full direct-wave evolution requires numerical-relativity calibration. We further show that approximate pole-zero pairing in the Kerr response motivates a minimal filter set that suppresses quasinormal-mode features while revealing source-trajectory information.

gr-qc↗
arXiv2026

Misinterpreting spin precession as orbital eccentricity in gravitational-wave signals

The increasing scope and breadth of gravitational wave detectors is providing the opportunity to explore new parameters in gravitational-wave astronomy. Eccentricity and spin-precession are two key observables to infer the origin of a gravitational wave (GW) source. The interpretation of GW source parameters can be plagued by degeneracy, such as the well-known degeneracy between mass and spin. As the field has explored new parameters, questions have been raised about possible degeneracies between eccentricity and spin-precession. Although some state-of-the-art models now include these effects individually, models that incorporate spin-precession and eccentricity are only in their infancy. Until models faithfully cover the complete parameter space of compact binary coalescence, our ability to correctly measure the source parameters and infer the formation of the binary is compromised. Here, we present a study of the distinguishability of these two key parameters in heavy binary black hole systems. We study merger-ringdown dominated systems with detector-frame total masses ranging between $200-300M_{\odot}$ and mass ratio ranging between $1-3$. Our work finds that there is indeed a degeneracy between eccentricity and spin-precession; however, it is a highly localized effect. We find that the misidentified eccentricity estimates get worse as the detector-frame total mass increases from $200M_{\odot}$ to $300M_{\odot}$, corresponding to progressively shorter signals in the detector band. Additionally, this misidentification is highly sensitive to the inclination angle of the source system. We provide quantifiable estimates of the potency of this degeneracy in addition to identifying some of the regions of parameter space where this degeneracy exists.

gr-qc↗
arXiv2026

Entropy and stability of an extremally charged Einstein-Born-Infeld thin shell

Spacetimes with a thin shell offer a framework where both the dynamical and the thermodynamical stability of the matter comprising the shell can be consistently studied. In the present work, we consider the dynamical and the thermodynamical stability of a spherical thin shell in Einstein gravity coupled to Born-Infeld electrodynamics. For our construction, we adopt the extremally charged solution of the theory, which gives a closed analytic form for the horizon location that allows for a clear derivation of the corresponding physical quantities of interest. Under this scenario, the dynamical stability conditions under radial perturbations are readily obtained in terms of an effective potential. The equilibrium thermodynamics for such a shell is presented. We find that, despite a non-zero pressure at the shell (unlike the extremally charged Reissner-Nordström counterpart), its entropy is solely characterized as a function of the gravitational radius. We propose a physically suitable \emph{ansatz} for the relevant equations of state in order to obtain a closed expression for the entropy density of the shell. We find that the thermodynamical stability conditions reduce to a single inequality related to exchanges of the charge at the shell, which determines the domain where both dynamical and thermodynamical stable configurations exist.

gr-qc↗