[Paper Review] Astrophysics with the Laser Interferometer Space Antenna

Pau Amaro‐Seoane, Jeff J. Andrews+157 more|arXiv (Cornell University)|Mar 11, 2022

Superconducting and THz Device Technology20 citations

TL;DR

A comprehensive review of LISA’s astrophysical landscape, covering ultra-compact stellar binaries, massive black hole binaries, and extreme/intermediate mass-ratio inspirals, and their modeling, data analysis, and multi-messenger potential.

ABSTRACT

The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it will offer unique opportunities to address many key astrophysical questions in a completely novel way. The synergy with ground-based and space-born instruments in the electromagnetic domain, by enabling multi-messenger observations, will add further to the discovery potential of LISA. The next decade is crucial to prepare the astrophysical community for LISA's first observations. This review outlines the extensive landscape of astrophysical theory, numerical simulations, and astronomical observations that are instrumental for modeling and interpreting the upcoming LISA datastream. To this aim, the current knowledge in three main source classes for LISA is reviewed; ultracompact stellar-mass binaries, massive black hole binaries, and extreme or intermediate mass ratio inspirals. The relevant astrophysical processes and the established modeling techniques are summarized. Likewise, open issues and gaps in our understanding of these sources are highlighted, along with an indication of how LISA could help making progress in the different areas. New research avenues that LISA itself, or its joint exploitation with upcoming studies in the electromagnetic domain, will enable, are also illustrated. Improvements in modeling and analysis approaches, such as the combination of numerical simulations and modern data science techniques, are discussed. This review is intended to be a starting point for using LISA as a new discovery tool for understanding our Universe.

Motivation & Objective

• Assess the astrophysical processes and environments relevant for interpreting LISA data.
• Summarize current modeling techniques and numerical simulations for LISA source classes.
• Highlight open questions, gaps, and how LISA can advance understanding of binary evolution and black hole demographics.
• Discuss multi-messenger synergies with electromagnetic observations and other GW detectors.
• Outline methodological tasks for improving simulations, data analysis, and inference approaches.

Proposed method

• Survey and synthesize current knowledge on three main LISA source classes: ultra-compact stellar binaries, massive black hole binaries, and EMRIs/IMRIs.
• Summarize formation channels, environmental effects, and evolution leading to LISA-detectable signals.
• Discuss modeling techniques including numerical simulations, semi-analytic methods, and machine learning/inference approaches.
• Identify open issues, gaps, and potential gains from multi-messenger observations.
• Propose strategies to maximize scientific return through EM counterparts and cross-mission synergies.

Experimental results

Research questions

• RQ1 What are the dominant astrophysical formation channels for LISA sources across the three main classes?
• RQ2 How do environments and dynamical processes influence GW signals and parameter estimation for LISA sources?
• RQ3 What are the expected rates and demographics of LISA-detectable binaries in the Milky Way and in extragalactic contexts?
• RQ4 How can multi-messenger observations complement GW data to constrain binary evolution and black hole demographics?
• RQ5 What methodological advances are needed to model, simulate, and interpret LISA data effectively?

Key findings

• Galactic WD+WD binaries are the dominant LISA foreground and thousands of resolved WD+WD systems are predicted, with several NS+NS and NS+WD systems also detectable.
• BH+BH binaries detectable by LISA can be observed out to hundreds of Mpc, enabling pre-merger insights before ground-based detectors see the final coalescence.
• EMRIs and IMRIs offer guaranteed or plausible science with rich information about galactic nuclei dynamics and stellar interactions near MBHs.
• Multi-messenger observations across EM bands and GW detectors will enhance localization, mass measurement, and understanding of binary evolution.
• A substantial need exists for improved modeling and data-analysis techniques, including ML approaches, to exploit LISA data fully.
• Verification binaries provide crucial benchmarks for instrument tests and early science returns.