Inspiral-merger-ringdown waveforms for black-hole binaries with non-precessing spins (0909.2867v3)

Abstract: We present the first analytical inspiral-merger-ringdown gravitational waveforms from binary black holes (BBHs) with non-precessing spins, that is based on a description of the late-inspiral, merger and ringdown in full general relativity. By matching a post-Newtonian description of the inspiral to a set of numerical-relativity simulations, we obtain a waveform family with a conveniently small number of physical parameters. These waveforms will allow us to detect a larger parameter space of BBH coalescence, including a considerable fraction of precessing binaries in the comparable-mass regime, thus significantly improving the expected detection rates.

• The paper introduces a unified waveform that seamlessly blends post-Newtonian inspiral data with numerical relativity merger and ringdown phases.
• The authors validate the model through extensive simulations using codes such as BAM, CCATIE, and LLAMA to ensure high amplitude and phase accuracy.
• Implementing these waveforms can significantly boost gravitational wave detection sensitivity and improve parameter estimation for black-hole binary searches.

Inspiral-Merger-Ringdown Waveforms for Black-Hole Binaries with Non-Precessing Spins

The paper "Inspiral-merger-ringdown waveforms for black-hole binaries with non-precessing spins" is a significant contribution to the domain of gravitational wave astrophysics, particularly in the modeling of gravitational waveforms from binary black-hole (BBH) mergers. This work addresses the development of an analytical waveform family that describes the coalescence process of BBHs with non-precessing spins. The construction of such waveforms is grounded in full general relativity and requires intricate modeling of the inspiral, merger, and ringdown stages of the binary evolution.

Algorithmic and Computational Framework

The authors of this paper have successfully derived a waveform template by matching post-Newtonian (PN) methods, which accurately describe the early inspiral stage, with numerical-relativity simulations that provide solutions for the late inspiral, merger, and ringdown phases. The integration of these two approaches results in an inspiral-merger-ringdown (IMR) waveform capable of capturing the dynamics of BBH systems up to arbitrary mass ratios and over a spectrum of spin configurations. The resulting waveform family is parametrized by the total mass $M$, symmetric mass ratio $\eta$, and an effective spin parameter $\chi$, simplifying the complexities that arise when models include up to six spin parameters.

Numerical Simulations and Hybrid Waveform Construction

Through exhaustive numerical simulations using codes such as BAM, CCATIE, and LLAMA, the authors have created datasets that cover multiple configurations, including equal-mass binaries with equal spins, and unequal-mass binaries with various spin alignments. These datasets provide the basis for constructing hybrid waveforms, which blend PN and numerical-relativity waveforms over overlapping temporal intervals. The simulations, conducted in a precision-oriented moving-puncture formalism, exhibit high-fidelity gravitational waves (GWs) concerning amplitude and phase accuracy, extending the efficacy of waveform models employed in GW searches.

Contribution to Detection Sensitivity and Parameter Estimation

Implementing the waveform templates presented in this paper can significantly enhance the detection rates of gravitational waves emanating from BBHs by broadening the parameter space for coalescence detection. Particularly, the templates are structured to improve the high signal-to-noise-ratio required for confident detections without compromising computational feasibility. Importantly, these waveforms maintain considerable detection efficacy for precessing binaries within the comparable mass regime, marking a step forward in understanding the dynamics of generic spinning binaries.

Practical Implications and Future Directions

The implications of these waveform models extend into several domains of astrophysical research. They bolster the sensitivity and accuracy of GW observatories such as LIGO and the upcoming Advanced LIGO, potentially increasing the astrophysical reach to several gigaparsecs, contingent upon high-spin configurations. This expanded reach in turn translates to increased BBH coalescence event rates. Furthermore, these models provide a scaffold for future enhancements which could incorporate non-quadrupole harmonics and more comprehensive coverage across mass and spin parameters.

In conclusion, this paper offers a foundational analytical tool that not only aligns well with current GW detection capabilities but which also has the potential to accelerate astrophysical research into BBH dynamics in a computationally efficient manner. Given the rapid progression in observational technology and computational methodologies, the continuation of this research will likely elucidate further complexities in the gravitational universe and enhance our comprehension of fundamental astrophysical phenomena.