[Paper Review] The Laser Interferometer Space Antenna: Unveiling the Millihertz Gravitational Wave Sky

John Baker, Jillian Bellovary+40 more|arXiv (Cornell University)|Jul 15, 2019

Pulsars and Gravitational Waves ResearchPhysics and Astronomy38 references115 citations

TL;DR

The paper outlines the LISA mission concept, science goals, architecture, and status, emphasizing millihertz gravitational-wave astronomy from a three-spacecraft constellation.

ABSTRACT

The first terrestrial gravitational wave interferometers have dramatically underscored the scientific value of observing the Universe through an entirely different window, and of folding this new channel of information with traditional astronomical data for a multimessenger view. The Laser Interferometer Space Antenna (LISA) will broaden the reach of gravitational wave astronomy by conducting the first survey of the millihertz gravitational wave sky, detecting tens of thousands of individual astrophysical sources ranging from white-dwarf binaries in our own galaxy to mergers of massive black holes at redshifts extending beyond the epoch of reionization. These observations will inform - and transform - our understanding of the end state of stellar evolution, massive black hole birth, and the co-evolution of galaxies and black holes through cosmic time. LISA also has the potential to detect gravitational wave emission from elusive astrophysical sources such as intermediate-mass black holes as well as exotic cosmological sources such as inflationary fields and cosmic string cusps.

Motivation & Objective

• Motivate the millihertz GW astronomy case and outline LISA's scientific objectives and expected impact.
• Present the LISA mission concept, architecture, and baseline performance targets.
• Summarize current status, partnerships, schedule, and NASA/ESA contributions and plans for US participation.

Proposed method

• Describe the LISA measurement concept using a 2.5 million km triangular constellation.
• Explain key performance drivers: test-mass acceleration noise and displacement measurement noise with Time-Delay Interferometry.
• Outline data analysis approaches including matched filtering and Bayesian/MCMC techniques and the role of Mock LISA Data Challenges.
• Summarize heritage from LISA Pathfinder and GRACE-FO LRI as flight demonstrations and technology readiness progress.
• Discuss mission organization, timelines, and cost/scenario considerations for international collaboration.

Experimental results

Research questions

• RQ1 What are the primary scientific objectives achievable with a millihertz gravitational-wave observatory?
• RQ2 How does the LISA design enable detection and characterization of diverse sources such as Galactic binaries, MBH mergers, EMRIs, and cosmological backgrounds?
• RQ3 What is the current status, organization, and schedule for ESA-led LISA with NASA contributions?
• RQ4 What are the key technologies and heritage that validate LISA's feasibility and performance?
• RQ5 How can US participation contribute to instrumentation, data analysis, and science exploitation?

Key findings

• LISA will conduct the first all-sky survey of millihertz gravitational waves, detecting tens of thousands of sources.
• Millions of compact binaries in the Milky Way will produce an ensemble of signals, with tens of thousands resolved individually and an unresolved foreground shaping sensitivity.
• LISA will observe extreme mass-ratio inspirals and massive black hole mergers across broad redshifts, enabling tests of gravity and cosmology.
• The mission concept includes a 2.5 million km triangular constellation in a heliocentric orbit, with robust sky localization for multimessenger follow-up.
• In-flight demonstrations (LISA Pathfinder, GRACE-FO LRI) have advanced TRL readiness and heritage for key subsystems; data challenges (MLDCs) prepare for complex signal extraction.
• The project emphasizes international collaboration (ESA-led with NASA contributions) and a staged schedule targeting Mission Adoption in the early 2020s with launch in the early 2030s.