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 quest for binary and dual supermassive black holes (SMBHs) at the dawn of the multi-
messenger era is compelling. Detecting dual active galactic nuclei (AGN)–active SMBHs at …

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 …

There is growing observational evidence for dwarf galaxies hosting active galactic nuclei
(AGN), including hints of AGN-driven outflows in dwarfs. However, in the common theoretical …

Despite traditional thinking, an appreciable population of massive black holes (that is, more
massive than stellar-mass black holes) may be lurking in dwarf galaxies. Before the last …

We analyse the demographics of black holes (BHs) in the large-volume cosmological
hydrodynamical simulation Horizon-AGN. This simulation statistically models how much gas …

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 …

Recent discoveries of massive black holes (MBHs) in dwarf galaxies suggest that they may
have a more common presence than once thought. Systematic searches are revealing more …

While the formation of the first black holes (BHs) at high redshift is reasonably well
understood though debated, massive BH formation at later cosmic epochs has not been …

We combine deep optical and radio data, from the Hyper Suprime-Cam and the Low-
Frequency Array (LOFAR), respectively, to study 78 radio active galactic nuclei (AGN) in …