LISA data analysis: The monochromatic binary detection and initial guess problems

TL;DR

This paper proposes a method for detecting monochromatic gravitational wave signals from binaries with LISA by dividing the sky into pixels and demodulating Doppler effects, improving initial parameter guesses for signal identification.

Contribution

It introduces a pixel-based demodulation approach to address detection and initial guess challenges in LISA gravitational wave data analysis.

Findings

Method effectively identifies signals in simulated data

Demodulation improves initial parameter estimation

Approach is promising for monochromatic binary searches

Abstract

We consider the detection and initial guess problems for the LISA gravitational wave detector. The detection problem is the problem of how to determine if there is a signal present in instrumental data and how to identify it. Because of the Doppler and plane-precession spreading of the spectral power of the LISA signal, the usual power spectrum approach to detection will have difficulty identifying sources. A better method must be found. The initial guess problem involves how to generate {\it a priori} values for the parameters of a parameter-estimation problem that are close enough to the final values for a linear least-squares estimator to converge to the correct result. A useful approach to simultaneously solving the detection and initial guess problems for LISA is to divide the sky into many pixels and to demodulate the Doppler spreading for each set of pixel coordinates. The demodulated power spectra may then be searched for spectral features. We demonstrate that the procedure works well as a first step in the search for gravitational waves from monochromatic binaries.