Beyond LISA: Exploring Future Gravitational Wave Missions

TL;DR

The paper evaluates how follow-on gravitational wave missions ALIA, ALIAS, LISAS, and BBO variants could enhance parameter estimation and sky localization compared to LISA. Using Fisher-information analyses with time-delay interferometry channels, it quantifies gains in angular resolution and distance measurements for IMBH binaries and stellar-mass binaries, across single and dual-constellation deployments. Key results show ALIAS and LISAS offer dramatic improvements in localization and distance precision, enabling three-dimensional IMBH mappings and host-galaxy identification, while BBO configurations can both detect a Gravitational Wave Background early and still deliver detailed astrophysical foreground catalogs. The findings inform mission design trade-offs between precision gravitational-wave astronomy and background detection capabilities.

Abstract

The Advanced Laser Interferometer Antenna (ALIA) and the Big Bang Observer (BBO) have been proposed as follow on missions to the Laser Interferometer Space Antenna (LISA). Here we study the capabilities of these observatories, and how they relate to the science goals of the missions. We find that the Advanced Laser Interferometer Antenna in Stereo (ALIAS), our proposed extension to the ALIA mission, will go considerably further toward meeting ALIA's main scientific goal of studying intermediate mass black holes. We also compare the capabilities of LISA to a related extension of the LISA mission, the Laser Interferometer Space Antenna in Stereo (LISAS). Additionally, we find that the initial deployment phase of the BBO would be sufficient to address the BBO's key scientific goal of detecting the Gravitational Wave Background, while still providing detailed information about foreground sources.

Figures (11)

• Figure 1: The proposed orbital configuration of the Big Bang Observer.
• Figure 2: Sensitivity curves for LISA, ALIA, and BBO with optimally filtered amplitude plots for equal mass binaries at $z = 1$ in their last year before coalescence. The masses shown are in units of solar masses. The squares denote the frequency one week from coalescence.
• Figure 3: Sensitivity curves for the $A, E$, and $T$ channels for ALIA with optimally filtered amplitude plots for equal mass binaries at $z = 1$ in their last year before coalescence. The masses shown are in units of solar masses. The squares denote the frequency one week from coalescence.
• Figure 4: Histograms of the parameter uncertainties and SNR, for equal mass binaries of $10^3 M_{\odot}$ at $z = 1$, as detected by ALIA.
• Figure 5: SNR histogram for ALIA and ALIAS from $10 M_{\odot}$ equal mass binaries at $z = 1$.