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 …

The existence of∼ 109M⊙ supermassive black holes (SMBHs) within the first billion years
of the Universe has stimulated numerous ideas for the prompt formation and rapid growth of …

The gravitational-wave signal GW190521 is consistent with a binary black hole (BBH)
merger source at redshift 0.8 with unusually high component masses, 85-14+ 21 M o and 66 …

Understanding the link between massive (≳ 30 M⊙) stellar black holes (BHs) and their
progenitor stars is a crucial step to interpret observations of gravitational-wave events. In this …

Intermediate-mass black holes (IMBHs), with masses in the range 1 0 0–1 0 6 M⊙, are the
link between stellar-mass BHs and supermassive BHs (SMBHs). They are thought to be the …

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 …

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 …

We present a sample of 40 active galactic nucleus (AGN) in dwarf galaxies at redshifts z≲
2.4. The galaxies are drawn from the Chandra COSMOS-Legacy survey as having stellar …

Intermediate-mass black holes should help us to understand the evolutionary connection
between stellar-mass and super-massive black holes. However, the existence of …