Very compact objects probe extreme gravitational fields and may be the key to understand
outstanding puzzles in fundamental physics. These include the nature of dark matter, the …

The idea of stable, localized bundles of energy has strong appeal as a model for particles. In
the 1950s, John Wheeler envisioned such bundles as smooth configurations of …

We present a review of the influence of cosmic repulsion and external magnetic fields on
accretion disks rotating around rotating black holes and on jets associated with these …

We present a directed search for continuous gravitational wave (CW) signals emitted by
spinning neutron stars located in the inner parsecs of the Galactic Center (GC). Compelling …

While singularities are inevitable in the classical theory of general relativity, it is commonly
believed that they will not be present when quantum gravity effects are taken into account in …

Gravitational wave astronomy provides an unprecedented opportunity to test the nature of
black holes and search for exotic, compact alternatives. Recent studies have shown that …

The combined study of the flaring of active galactic nuclei (AGNs) at radio wavelengths and
parsec-scale jet kinematics with Very Long Baseline Interferometry has led to the view that …

ABSTRACT OJ287 is the best candidate active galactic nucleus (AGN) for hosting a
supermassive binary black hole (SMBBH) at very close separation. We present 120 Very …

The Galactic centre supermassive black hole (SMBH), in sharp contrast with its complex
environment, is characterized by only three classical parameters–mass, spin, and electric …

We present a review of the Penrose process and its modifications in relation to the Kerr
black holes and naked singularities (superspinars). We introduce the standard variant of this …