The open-access journal Living Reviews in Relativity has published two new review articles in March 2023:
Amaro-Seoane, P., Andrews, J., Arca Sedda, M. et al.
Astrophysics with the Laser Interferometer Space Antenna.
Living Rev Relativ 26, 2 (2023).
Summary: 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 current knowledge in three main source classes for LISA is reviewed; ultra-compact 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.
Note: This article is part of a new joint Topical Collection between Living Reviews and the journal General Relativity and Gravitation (https://link.springer.com/collections/bhdbjdhdhg).
Liebling, S.L., Palenzuela, C.
Dynamical boson stars.
Living Rev Relativ 26, 1 (2023).
Summary: (Major revision, updates and expands the 2017 version.)
The idea of stable, localized bundles of energy has strong appeal as a model for particles. In the 1950s, John Wheeler envisioned such bundles as smooth configurations of electromagnetic energy that he called geons, but none were found. Instead, particle-like solutions were found in the late 1960s with the addition of a scalar field, and these were given the name boson stars. Since then, boson stars find use in a wide variety of models as sources of dark matter, as black hole mimickers, in simple models of binary systems, and as a tool in finding black holes in higher dimensions with only a single Killing vector. We discuss important varieties of boson stars, their dynamic properties, and some of their uses, concentrating on recent efforts.