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 observations of ultraluminous X-ray sources (ULXs). X-ray spectroscopic and
timing studies of ULXs suggest a new accretion state distinct from those seen in Galactic …

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 …

We perform a comprehensive study of the X-ray emission from 70 transient sources that
have been classified as tidal disruption events (TDEs) in the literature. We explore the …

ABSTRACT I consider quasi-periodic eruptions (QPEs) from galaxy nuclei. All the known
cases fit naturally into a picture of accretion from white dwarfs (WDs) in highly eccentric …

Ultraluminous X-ray sources (ULXs) are accreting black holes that may contain the missing
population of intermediate mass black holes or reflect super-Eddington accretion physics …

Most galactic nuclei harbor a massive black hole (MBH), whose birth and evolution are
closely linked to those of its host galaxy. The unique conditions near the MBH—high velocity …

Massive black holes often exist within dwarf galaxies, and both simulations and
observations have shown that a substantial fraction of these may be off-centre with respect …

We present the results from an X-ray and optical study of a new sample of eight extreme
luminosity ultraluminous X-ray source (ULX) candidates, which were selected as the …

Stars grazing supermassive black holes (SMBHs) on bound orbits may survive tidal
disruption, causing periodic flares. Inspired by the recent discovery of the periodic nuclear …