LISA Data Analysis: Doppler Demodulation

Neil J. Cornish
Shane L. Larson, Utah State University

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Originally published by Institute of Physics in Classical and Quantum Gravity. Publisher version available thought this remote link, subscription is required.

Author post print is also available at arXiv.org and is available for download through link above.

Abstract

The orbital motion of the Laser Interferometer Space Antenna (LISA) produces amplitude, phaseand 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 deleteriousaffect of spreading a signal across a wide bandwidth, thereby reducing the strength of the signalrelative 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 andfrequencies of the brightest gravitational wave sources.