Tomographic approach to resolving the distribution of LISA Galactic binaries

TL;DR

This paper presents a tomographic method to reconstruct the distribution of Galactic white dwarf binaries observed by LISA, using Doppler modulation effects to infer their frequency and sky position.

Contribution

It introduces a linear tomographic approach that reconstructs the binary population distribution from LISA data, accounting for Doppler modulation and noise.

Findings

Successful recovery of binary sources in simulated noisy data

Demonstration of the method's ability to reconstruct distributions from a delta function

Analysis of the point spread function for source localization

Abstract

The space based gravitational wave detector LISA is expected to observe a large population of Galactic white dwarf binaries whose collective signal is likely to dominate instrumental noise at observational frequencies in the range 10^{-4} to 10^{-3} Hz. The motion of LISA modulates the signal of each binary in both frequency and amplitude, the exact modulation depending on the source direction and frequency. Starting with the observed response of one LISA interferometer and assuming only doppler modulation due to the orbital motion of LISA, we show how the distribution of the entire binary population in frequency and sky position can be reconstructed using a tomographic approach. The method is linear and the reconstruction of a delta function distribution, corresponding to an isolated binary, yields a point spread function (psf). An arbitrary distribution and its reconstruction are related via smoothing with this psf. Exploratory results are reported demonstrating the recovery of binary sources, in the presence of white Gaussian noise.