Related papers: Nuclear Rings in Galaxies---A Kinematic Perspectiv…

Nuclear rings, prevalent in barred galaxies, are essential to understanding gas transport toward galactic nuclei. However, the peculiar nuclear ring in our neighboring galaxy M31 remains poorly understood. Here we present a comprehensive…

All the four giant planets in our Solar System have rings, but their characteristics are very different. The rings consist of a number of small particles, although individual particles have not been directly imaged. Near the central planet,…

We present sub-arcsecond resolution ground-based near-infrared images of the central regions of a sample of twelve barred galaxies with circumnuclear star formation activity, which is organized in ring-like regions typically one kiloparsec…

In Debattista et al. (2015), we proposed that a kiloparsec-scale nuclear disc is responsible for the high-velocity secondary peak in the stellar line-of-sight velocity distributions (LOSVDs) seen at positive longitudes in the bulge by the…

We have compiled high-resolution position-velocity diagrams observed along the major axes of nearby spiral galaxies in the CO-line emission, and derived rotation curves for the inner regions of the galaxies. We have combined the inner…

Sticky particle calculations indicate that a coherent structure, a dispersion ring, forms when a cloud on a low angular momentum orbit passes close to the dynamical center of an isothermal sphere containing a central point mass. The cloud…

The recent discovery of narrow rings around minor bodies has raised many questions regarding their origin and current dynamics. Sharp ring boundaries seem indicative of shepherding moonlets, but none have been found. All rings lie close to…

Star clusters that form in nuclear rings appear to be at slightly larger radii than the gas. We argue that the star clusters move out from the gas in which they are formed because of satellite-disk tidal interactions. In calculating the…

The innermost regions of most galaxies are characterised by the presence of extremely dense nuclear star clusters. Nevertheless, these clusters are not the only stellar component present in galactic nuclei, where larger stellar structures…

Since 2013, dense and narrow rings are known around the small Centaur object Chariklo and the dwarf planet Haumea. Dense material has also been detected around the Centaur Chiron, although its nature is debated. This is the first time ever…

This thesis explores compact objects, particularly neutron stars, focusing on their properties, classification, and stability within the framework of general relativity. Two distinct studies are presented. The first study examines the…

We investigate the structural properties of nuclear star clusters in late-type spiral galaxies. More specifically, we fit analytical models to HST images of 39 nuclear clusters in order to determine their effective radii after correction…

We present results from a photometric H-alpha survey of 22 nuclear rings, aiming to provide insight into their star formation properties, including age distribution, dynamical timescales, star formation rates, and galactic bar influence. We…

The rotating nuclei represent one of most interesting subjects for theoretical and experimental studies. They open a new dimension of nuclear landscape, namely, spin direction. Contrary to the majority of nuclear systems, their properties…

Dense and narrow rings have been discovered recently around the small Centaur object Chariklo and the dwarf planet Haumea, while being suspected around the Centaur Chiron. They are the first rings observed in the Solar System elsewhere than…

Recent observations have shown that compact nuclear star clusters (NSCs) are present in up to 80% of galaxies. However, detailed studies of their dynamical and chemical properties are confined mainly to spiral galaxy hosts, where they are…

The study of stellar kinematic properties may provide hints on the formation and evolution of elliptical and lenticular galaxies. Although most previous studies have focused on the large scale of these galaxies, their central regions…

The role of gas in the mass assembly at the nuclei of galaxies is still subject to some uncertainty. Stellar nuclear discs bridge the gap between the large-scale galaxy and the central massive objects that reside there. Using a high…

The shape of a cusped galactic nucleus is constrained by the range of shapes of orbits in its gravitational potential. It is shown for scale-free non-axisymmetric discs that while a plausible elongated density model requires at least some…

Determining the differential-rotation law of compact stellar objects produced in binary neutron stars mergers or core-collapse supernovae is an old problem in relativistic astrophysics. Addressing this problem is important because it…