Pointing LISA-like gravitational wave detectors

TL;DR

This paper discusses how the initial orientation of LISA-like space-based gravitational wave detectors affects their sky sensitivity and how it can be optimized or suppressed for specific sources by choosing initial spacecraft configurations.

Contribution

It introduces the concept of pointing LISA-like detectors by selecting initial orientations to optimize sensitivity to known sources.

Findings

Initial orientation influences detector sensitivity patterns.

Orientation choice can enhance detection of specific sky regions.

Nulls in response can be strategically placed.

Abstract

Space-based gravitational wave detectors based on the Laser Interferometer Space Antenna (LISA) design operate by synthesizing one or more interferometers from fringe velocity measurements generated by changes in the light travel time between three spacecraft in a special set of drag-free heliocentric orbits. These orbits determine the inclination of the synthesized interferometer with respect to the ecliptic plane. Once these spacecraft are placed in their orbits, the orientation of the interferometers at any future time is fixed by Kepler's Laws based on the initial orientation of the spacecraft constellation, which may be freely chosen. Over the course of a full solar orbit, the initial orientation determines a set of locations on the sky were the detector has greatest sensitivity to gravitational waves as well as a set of locations where nulls in the detector response fall. By artful choice of the initial orientation, we can choose to optimize or suppress the antennas sensitivity to sources whose location may be known in advance (e.g., the Galactic Center or globular clusters).