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

Black hole and neutron star X-ray binary systems routinely show quasi-periodic oscillations
(QPOs) in their X-ray flux. Despite being strong, easily measurable signals, their physical …

In the past two decades, high-amplitude electromagnetic outbursts have been detected from
dormant galaxies and often attributed to the tidal disruption of a star by the central black …

Black hole (BH) accretion flows and jets are qualitatively affected by the presence of ordered
magnetic fields. We study fully 3D global general relativistic magnetohydrodynamic (MHD) …

There have recently been several reports of apparently periodic variations in the light curves
of quasars, eg PG 1302− 102 by Graham et al. Any quasar showing periodic oscillations in …

With the availability of the large database of black-hole transients from the Rossi X-Ray
Timing Explorer, the observed phenomenology has become very complex. The original …

The production of artificial light curves with known statistical and variability properties is of
great importance in astrophysics. Consolidating the confidence levels during cross …

The advent of the Event Horizon Telescope (EHT), a millimeter-wave very long baseline
interferometric array, has enabled spatially resolved studies of the subhorizon-scale …

X-ray quasi-periodic eruptions (QPEs) were discovered recently in active galaxies with an
unknown driving mechanism. Under the assumption that QPEs are caused by star–disk …

The close neighborhood of a supermassive black hole contains not only the accreting gas
and dust but also stellar-sized objects, such as late-type and early-type stars and compact …