Quasinormal modes are eigenmodes of dissipative systems. Perturbations of classical
gravitational backgrounds involving black holes or branes naturally lead to quasinormal …

This review covers the main aspects of black hole accretion disk theory. We begin with the
view that one of the main goals of the theory is to better understand the nature of black holes …

Abstract Narrow-line Seyfert 1 (NLS1) galaxies have low-mass black holes and mass
accretion rates close to (or exceeding) Eddington, so a standard blackbody accretion disc …

We review how the recent increase in X-ray and radio data from black hole and neutron star
binaries can be merged together with theoretical advances to give a coherent picture of the …

General relativity has passed all solar system experiments and neutron star based tests,
such as binary pulsar observations, with flying colors. A more exotic arena for testing …

The spins of ten stellar black holes have been measured using the continuum-fitting method.
These black holes are located in two distinct classes of X-ray binary systems, one that is …

Stellar-mass black holes and neutron stars represent extremes in gravity, density, and
magnetic fields. They therefore serve as key objects in the study of multiple frontiers of …

We show that the low-frequency quasi-periodic oscillations (QPOs) seen in the power-
density spectra of black hole binaries (and neutron stars) can be explained by the Lense …

We investigate how the total radio luminosity of AGN-powered radio sources depends on
their accretion luminosity and the central black hole mass. Our studies cover about 7 orders …

We revisit the question of the nature of ultraluminous X-ray sources (ULXs) through a
detailed investigation of their spectral shape, using the highest quality X-ray data available …