We report spectroscopic and photometric follow-up of a dormant black hole (BH) candidate
from Gaia DR3. The system, which we call Gaia BH2, contains a∼ 1 M⊙ red giant and a …

Massive stars play a major role in the evolution of their host galaxies and serve as important
probes of the distant Universe. It has been established that the majority of massive stars …

Population-synthesis codes are an unique tool to explore the parameter space of massive
binary star evolution and binary compact object (BCO) formation. Most population-synthesis …

Abstract Compact Object Mergers: Population Astrophysics and Statistics (COMPAS;
https://compas. science) is a public rapid binary population synthesis code. COMPAS …

Dense star clusters are spectacular self-gravitating stellar systems in our Galaxy and across
the Universe—in many respects. They populate disks and spheroids of galaxies as well as …

Most massive stars are members of a binary or a higher-order stellar system, where the
presence of a binary companion can decisively alter their evolution via binary interactions …

Mergers of black hole–neutron star (BHNS) binaries have now been observed by
gravitational wave (GW) detectors with the recent announcement of GW200105 and …

Making the most of the rapidly increasing population of gravitational-wave detections of
black hole (BH) and neutron star (NS) mergers requires comparing observations with …

Rapid binary population synthesis codes are often used to investigate the evolution of
compact-object binaries. They typically rely on analytical fits of single-star evolutionary …

Gravitational-wave astronomy has revealed a population of stellar-mass black holes more
massive than observed previously by other means. The maximum mass of black holes …