The compact and, with ∼ 4.3 ± 0.3 * 10^ 6∼ 4.3±0.3× 10 6 M _ ⊙⊙, very massive object
located at the center of the Milky Way is currently the very best candidate for a supermassive …

For many years we have known that dust in the form of a dusty-molecular torus is
responsible for the obscuration in active galactic nuclei (AGN) at large viewing angles and …

In this contribution, we summarize our results concerning the observational constraints on
the electric charge associated with the Galactic centre black hole–Sgr A*. According to the …

The origin of the broad line region (BLR) in active galaxies remains unknown. It seems to be
related to the underlying accretion disk, but an efficient mechanism is required to raise the …

We selected a sample of eight bright unobscured (at least at the iron line energy) Seyfert
galaxies observed simultaneously by XMM-Newton and BeppoSAX, taking advantage of the …

The spectra of active galactic nuclei exhibit broad-emission lines that presumably originate
in the broad-line region (BLR) with gaseous-dusty clouds in a predominantly Keplerian …

Astrophysical fluids may acquire nonzero electrical charge because of strong irradiation or
charge separation in a magnetic field. In this case, electromagnetic and gravitational forces …

A general superposed solution between a Schwarzschild black hole and one of the first
family of Lemos-Letelier disks with two opposite dipoles is given. For the Newtonian core …

Exact solutions to Einsteins equations have been useful for the understanding of general
relativity in many respects. They have led to physical concepts as black holes and event …

We present a relativistic model describing a thin disk surrounded by a halo in the presence
of an electromagnetic field. The model is obtained by solving the Einstein-Maxwell …