FastEMRIWaveforms: New tools for millihertz gravitational-wave data analysis

TL;DR

The paper introduces the FastEMRIWaveforms package, which provides GPU-accelerated tools for generating and analyzing relativistic EMRI gravitational waveforms, improving efficiency and accuracy for data analysis in millihertz gravitational-wave astronomy.

Contribution

It presents new GPU-accelerated waveform models, including an improved Augmented Analytic Kludge, and demonstrates their application in EMRI parameter estimation and bias analysis.

Findings

Relativistic EMRI waveforms can be generated with fewer harmonic modes without bias.

GPU acceleration significantly speeds up waveform generation and analysis.

Semi-relativistic amplitudes can cause biases in parameter estimation.

Abstract

We present the FastEMRIWaveforms (FEW) package, a collection of tools to build and analyze extreme mass ratio inspiral (EMRI) waveforms. Here, we expand on the Physical Review Letter that introduced the first fast and accurate fully-relativistic EMRI waveform template model. We discuss the construction of the overall framework; constituent modules; and the general methods used to accelerate EMRI waveforms. Because the fully relativistic FEW model waveforms are for now limited to eccentric orbits in the Schwarzschild spacetime, we also introduce an improved Augmented Analytic Kludge (AAK) model that describes generic Kerr inspirals. Both waveform models can be accelerated using graphics processing unit (GPU) hardware. With the GPU-accelerated waveforms in hand, a variety of studies are performed including an analysis of EMRI mode content, template mismatch, and fully Bayesian Markov Chain Monte Carlo-based EMRI parameter estimation. We find relativistic EMRI waveform templates can be generated with fewer harmonic modes ($\sim10-100$) without biasing signal extraction. However, we show for the first time that extraction of a relativistic injection with semi-relativistic amplitudes can lead to strong bias and anomalous structure in the posterior distribution for certain regions of parameter space.