The first generation of stars, often called Population III (or Pop III), form from metal-free
primordial gas at redshifts z∼ 30 and below. They dominate the cosmic star-formation …

Now that detection of gravitational-wave signals from the coalescence of extra-galactic
compact binary star mergers has become nearly routine, it is intriguing to consider other …

Gravitational waves enable tests of general relativity in the highly dynamical and strong-field
regime. Using events detected by LIGO-Virgo up to 1 October 2019, we evaluate the …

The first observation of gravitational waves from the inspiral of a binary neutron star (BNS)
200 system on 2017 August 17 (Abbott et al. 2017b) was a major landmark in multi …

Pulsar timing data used to provide upper limits on a possible stochastic gravitational wave
background (SGWB). However, the NANOGrav Collaboration has recently reported strong …

Gravitational waves provide a unique tool for observational astronomy. While the first LIGO–
Virgo catalogue of gravitational-wave transients (GWTC-1) contains 11 signals from black …

We revisit the possibility that the stochastic common-spectrum process recently detected by
the NANOGrav pulsar timing array experiment could be due to primordial gravitational …

Gravitational-wave observations have become an important new means to learn about the
Universe. The LIGO Scientific Collaboration and the Virgo Collaboration (LVC) have …

As gravitational-wave detectors become more sensitive and broaden their frequency
bandwidth, we will access a greater variety of signals emitted by compact binary systems …

Black hole superradiance is a powerful probe of light, weakly coupled hidden sector
particles. Many candidate particles, such as axions, generically have self-interactions that …