LISA data analysis I: Doppler demodulation

TL;DR

This paper presents a straightforward Doppler demodulation method for LISA gravitational wave signals, enhancing source localization and signal strength by reassembling dispersed power into a narrow frequency spike.

Contribution

It introduces a simple technique to remove Doppler modulation effects, improving detection and localization of monochromatic gravitational wave sources with LISA.

Findings

Effective reassembly of signal power into narrow spikes

Improved source localization and frequency determination

Potential for rapid identification of bright sources

Abstract

The orbital motion of the Laser Interferometer Space Antenna (LISA) produces amplitude, phase and frequency modulation of a gravitational wave signal. The modulations have the effect of spreading a monochromatic gravitational wave signal across a range of frequencies. The modulations encode useful information about the source location and orientation, but they also have the deleterious affect of spreading a signal across a wide bandwidth, thereby reducing the strength of the signal relative to the instrument noise. We describe a simple method for removing the dominant, Doppler, component of the signal modulation. The demodulation reassembles the power from a monochromatic source into a narrow spike, and provides a quick way to determine the sky locations and frequencies of the brightest gravitational wave sources.