We describe ongoing searches for intermediate-mass black holes with M BH≈ 10–105 M⊙.
We review a range of search mechanisms, both dynamical and those that rely on accretion …

We review the current knowledge about nuclear star clusters (NSCs), the spectacularly
dense and massive assemblies of stars found at the centers of most galaxies. Recent …

The Λ CDM cosmology passes demanding tests that establish it as a good approximation to
reality. The theory is incomplete, of course, and open issues are being examined in active …

Motivated by the recent detection of gravitational waves from the black hole binary merger
GW150914, we study the dynamical evolution of (stellar-mass) black holes in galactic nuclei …

We present a sample of 151 dwarf galaxies (10 8.5≲ M⋆≲ 10 9.5 M☉) that exhibit optical
spectroscopic signatures of accreting massive black holes (BHs), increasing the number of …

Supermassive black holes (BHs) have been found in 85 galaxies by dynamical modeling of
spatially resolved kinematics. The Hubble Space Telescope revolutionized BH research by …

Evidence shows that massive black holes reside in most local galaxies. Studies have also
established a number of relations between the MBH mass and properties of the host galaxy …

We derive improved versions of the relations between supermassive black hole mass (M
BH) and host-galaxy bulge velocity dispersion (σ) and luminosity (L; the M–σ and M–L …

According to the virial theorem, all gravitational systems in equilibrium sit on a plane in the
three-dimensional parameter space defined by their mass, size, and second moment of the …

Since the 1960s, when the connection between quasar energetics and supermassive black
holes was first established, galactic nuclei have remained objects of intense interest to …