arXiv subjects

Chad Henshaw

Publications and source records attributed to Chad Henshaw.

5 recordsLinked to original sources

arXiv2026

Gravitational Wave Hyperbolic Catalog: Reanalyzing High-Mass Gravitational Wave Signals Using Hyperbolic Waveforms

Close hyperbolic encounters between black holes produce distinctive bursts of gravitational radiation with a time-frequency morphology that is qualitatively different from that of quasi-circular inspirals. Expected to arise in dense stellar environments through dynamical interactions, these encounters probe formation channels and mass ranges inaccessible to isolated binary evolution, making them a compelling target for current and next-generation detectors. In this work, we reanalyze \totalevents high-mass events from the LIGO-Virgo-KAGRA catalogs using the hyperbolic configuration of the~\dali~waveform model. We compare these with analyses using the quasi-circular, precessing configuration of the same model, computing Bayes factors to evaluate which description is favored by the data. We find that most events strongly to mildly favor the quasi-circular, precessing scenario, except for GW190521. For this event, we find that the signal is best fit by a dynamical capture waveform, with Bayes factor $\ln \mathcal{B}^{\rm hyp}_{\rm prec}=3.71^{+0.11}_{-0.11}$. We confirm this preference via further analyses with~\dali~in different configurations (quasi-circular, non-precessing; eccentric, non-precessing; and eccentric, precessing), as well as one using the quasi-circular, precessing numerical relativity surrogate model \nrsur. We also highlight the results we obtain for GW231123, another high-mass signal linked to evidence of strong precession, for which we find strong preference for the quasi-circular, precessing scenario, with $\ln \mathcal{B}^{\rm hyp}_{\rm prec}=-15.80^{+0.24}_{-0.24}$. The analysis of mock signals generated with the best fitting waveforms for GW190521 and GW231123 suggest that the former might belong to a region of parameter space where high-mass, bound, precessing signals can be hard to distinguish from dynamical captures in parameter estimation.

gr-qc↗

arXiv2025

Parameter estimation of gravitational waves from hyperbolic black hole encounters

Systems of two black holes with unbound orbits can produce a diverse array of gravitational wave signals with rich morphology. This parameter space encompasses both hyperbolic orbit scattering events and dynamical captures, including zoom-whirl orbits with multiple flybys and direct plunge mergers. These signals challenge traditional parameter estimation infrastructure, which is largely optimized for quasicircular inspiral binaries. In this work we discuss the adaptation of the Rapid Iterative FiTting (RIFT) algorithm to this problem using the TEOBResumSDALI waveform model which can simulate generic orbits. We present results from a study of simulated signals emulating a scatter and plunge event, utilizing the design sensitivity of the forthcoming Cosmic Explorer interferometer. Our analysis demonstrates that RIFT accurately recovers the mass, spins, and hyperbolic orbit parameters: the system energy and angular momentum defined at a fiducial initial separation.

gr-qc↗

arXiv2025

Visualization of time-frequency structures in gravitational wave signals

The gravitational wave signals produced by the coalescence of compact binaries progress through three stages: inspiral, merger, and postmerger. The evolution of their frequency follows a slow build up during the inspiral that peaks at merger, forming the characteristic "chirp" pattern in the signal's time-frequency map. Herein we introduce a framework for localizing further characteristic structures in the time-frequency space of gravitational wave signals using the continuous wavelet transform. We consider two example cases where there are specific patterns in the postmerger stage of the signal that are rich with information on the physical nature of the source: highly-inclined black hole binaries with asymmetric mass ratio, and neutron star binaries with postmerger remnant oscillations. It is demonstrated that the choice of quality factor $Q$ plays a central role in distinguishing the postmerger features from that of the inspiral, with black hole systems preferring lower $Q$ and neutron star systems preferring higher $Q$. Furthermore, we demonstrate the use of chirplets as the wavelet transform basis, which allow for manipulation of structure in the time-frequency map.

gr-qc↗

arXiv2025

Time-frequency structure in the post-merger binary black hole gravitational wave signal

Gravitational wave signals from asymmetric binary black hole systems have been shown to exhibit additional chirps beyond the primary merger chirp in the post-merger region of the time-frequency domain. These secondary post-merger chirps correlate to the evolving geometry of the common horizon that forms as the binary merges and were previously studied through numerical relativity simulation in a zero-spin regime. In this work, we investigate the post-merger time-frequency structure in systems with both aligned and precessing spin using widely available waveform models. We find that the inclusion of strong aligned spin $\left(ξ= 0.75\right)$ induces further post-merger time-frequency peaks. Additionally we show that even mild precessing spin $\left(χ_p = 0.25\right)$ strongly affects the distribution of post-merger radiative power across the celestial sky of the final black hole. Our results support the theory of a correlation between the post-merger signal and horizon geometry.

gr-qc↗

arXiv2022

Implementation of a generalized precession parameter in the RIFT parameter estimation algorithm

Since the initial discovery of gravitational waves in 2015, significant developments have been made towards waveform interpretation and estimation of compact binary source parameters. We present herein an implementation of the generalized precession parameter $\langle χ_p \rangle$, which averages over all angular variations on the precession timescale, within the RIFT parameter estimation framework. Relative to the originally-proposed precession parameter $χ_p$, which characterizes the single largest dynamical spin in a binary, this new parameter $\langle χ_p \rangle$ has a unique domain $1 < \langle χ_p \rangle < 2$, which is exclusive to binaries with two precessing spins. After reviewing the physical differences between these two parameters, we describe how $\langle χ_p \rangle$ was implemented in RIFT and apply it to all 36 events from the second half of the Advanced LIGO and Advanced Virgo third operating run (O3b). In O3b, ten events show significant amounts of precession $\langle χ_p \rangle > 0.5$. Of particular interest is GW191109_010717; we show it has a $\sim28\%$ probability that the originating system necessarily contains two misaligned spins.

gr-qc↗