The spin of a black hole is an important quantity to study, providing a window into the
processes by which a black hole was born and grew. Furthermore, spin can be a potent …

The central engines of active galactic nuclei (AGNs) are powered by accreting supermassive
black holes, and while AGNs are known to play an important role in galaxy evolution, the key …

Active galactic nuclei (AGN) are energetic astrophysical sources powered by accretion onto
supermassive black holes in galaxies, and present unique observational signatures that …

Hard X-ray (≥ 10 keV) observations of active galactic nuclei (AGNs) can shed light on some
of the most obscured episodes of accretion onto supermassive black holes. The 70-month …

We present a broad-band spectral analysis of the joint XMM–Newton and Nuclear
Spectroscopic Telescope Array observational campaign of the narrow-line Seyfert 1 SWIFT …

The geometry of the accretion flow around stellar-mass black holes can change on
timescales of days to months,–. When a black hole emerges from quiescence (that is, it 'turns …

Accreting black holes emit highly collimated radio jets expanding at speeds approaching
light speed. Some of these jets appear to be expanding at superluminal speeds due to …

Luminous accreting stellar mass and supermassive black holes produce power–law
continuum X-ray emission from a compact central corona. Reverberation time lags occur …

The focusing optics of NuSTAR have enabled high signal-to-noise ratio spectra to be
obtained from many X-ray bright active galactic nuclei (AGN) and galactic black hole …

We present the drastic transformation of the X-ray properties of the active galactic nucleus
(AGN) 1ES 1927+ 654, following a changing-look event. After the optical/ultraviolet outburst …