Boson Stars and Oscillatons: A Review

TL;DR

This review discusses various bosonic compact objects like boson stars, oscillons, and Proca stars, highlighting their properties, formation, and potential observational signatures in astrophysics and dark matter research.

Contribution

It provides a comprehensive overview of the recent progress and key properties of bosonic compact objects, summarizing theoretical and observational developments.

Findings

Boson stars can mimic black holes in observations.

Oscillatons and boson stars are potential dark matter candidates.

Recent advances have improved understanding of bosonic object stability and detection methods.

Abstract

Compact objects occupy a pivotal role in the exploration of Nature. The interest spans from the role of compact objects in astrophysics to their detection through various methods (gravitational waves interferometry, microlensing, imaging). While the existence of compact objects made of fermions (neutron stars and white dwarfs) has been assessed, a parallel search for localized solitons made of bosons is ongoing, stemming from Wheeler's original proposal of electromagnetic "geons". Boson fields can clump up and form compact objects such as boson stars (for complex scalar fields), oscillons and oscillatons (for real scalar fields), or Proca stars (for massive vector fields), which can show up in searches as black hole mimickers, dark matter sources, and a variety of other phenomena. I review some crucial properties of these bosonic systems, including recent progress in the field.