Abstract The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders
about the fundamental theory of nature at play in the extreme gravity regime, where the …

In this article, we provide a review of the current state of the research of the black hole
shadow, focusing on analytical (as opposed to numerical and observational) studies. We …

Very compact objects probe extreme gravitational fields and may be the key to understand
outstanding puzzles in fundamental physics. These include the nature of dark matter, the …

In this paper, which is of programmatic rather than quantitative nature, we aim to further
delineate and sharpen the future potential of the LISA mission in the area of fundamental …

70 AIM, UMR 7158, CEA/DRF, CNRS, Université Paris Diderot, Irfu/Service d'Astrophysique,
Centre de Saclay, FR-91191 Gif-sur-Yvette, France

It is commonly believed that the ringdown signal from a binary coalescence provides a
conclusive proof for the formation of an event horizon after the merger. This expectation is …

Macroscopic objects, as we see them all around us, are governed by a variety of forces,
derived from a variety of approximations to a variety of physical theories. In contrast, the only …

Ultracompact objects with light rings (LRs) but without an event horizon could mimic black
holes (BHs) in their strong gravity phenomenology. But are such objects dynamically viable …

The existence of black holes and spacetime singularities is a fundamental issue in science.
Despite this, observations supporting their existence are scarce, and their interpretation is …

Can a dynamically robust bosonic star (BS) produce an (effective) shadow that mimics that
of a black hole (BH)? We focus on models of spherical BSs with free scalar or vector fields …