相关论文: Can galactic nuclei be non-axisymmetric? --- The p…
Galactic nuclei are now generally thought to have density cusps in their centres, and the evidence is mounting that as a consequence they are unlikely to be triaxial. Self-consistent stellar dynamical models of non-axisymmetric cusps would…
We introduce a new class of 2-D mass models, whose potentials are of St\"ackel form in elliptic coordinates. Our model galaxies have two separate strong cusps that form double nuclei. The potential and surface density distributions are…
We present cuspy, non-axisymmetric, scale-free mass models of discs, whose gravitational potentials are of St\"ackel form in parabolic coordinates. A black hole may be added at the centre, without in any way affecting the St\"ackel form;…
Recently, observations with the Hubble Space Telescope have revealed small stellar discs embedded in the nuclei of a number of ellipticals and S0s. In this paper we construct two-integral axisymmetric models for such systems. We calculate…
A comlex structure of nuclear disks of normal spiral galaxies was illustrated on the example of five galaxies, observed at 6m telescope. A problem of gravitational stability of nuclear disks is shortly discussed.
The stellar surface mass density profiles at the centers of typical ~L* and lower-mass spheroids exhibit power law 'cusps' with $\Sigma \propto R^(-n)$, where 0.5<n<1 for radii ~1-100 pc. Observations and theory support models in which…
Hubble Space Telescope (HST) observations reveal that the density of stars in most elliptical galaxies rises toward the center in a power-law cusp. Many of these galaxies also contain central dark objects,possibly supermassive black holes.…
For a sample of 22 core ellipticals and 22 power law ellipticals, I examine the apparent axis ratios of isophotes as a function of the dynamical time at the isophote's mean radius. The two types of elliptical galaxy have a significantly…
The consequences of nuclear black holes for the structure and dynamics of stellar spheroids are reviewed. Slow growth of a black hole in a pre-existing core produces a steep power-law density profile similar to the cusps seen in faint…
AIMS. The amplitude and scaleheight of the Galactic gas disc density are not axisymmetric against expectations in a self-gravity axisymmetric disc. However, this lopsidedness can be explained in terms of intergalactic accretion flows, which…
We present surface photometry for the central regions of a sample of 33 early-type (E, S0, and S0/a) galaxies observed at 1.6 microns (H band) using the Hubble Space Telescope (HST). We employ a new technique of two-dimensional fitting to…
The nuclear star cluster surrounding the massive black hole at the Galactic Centre consists of young and old stars, with most of the stellar mass in an extended, cuspy distribution of old stars. The compact cluster of young stars was…
Astrophysical discs which are sufficiently massive and cool are linearly unstable to the formation of axisymmetric structures. In practice, linearly stable discs of surface density slightly below the threshold needed for this instability…
Non-axisymmetric structures, such as bars and spiral arms, are known to concentrate molecular gas and star formation in galaxy centers, actively building up the pseudo-bulges. However, a direct link between the neutral (i.e., molecular and…
We have obtained HST_NICMOS images for 72 nearby spiral galaxy bulges in the H-band. These data show that galaxies with regular bulges have steeper nuclear cusps than galaxies with irregular bulges. We also show that galaxies with regular…
We combine DensePak integral field unit and TAURUS Fabry-Perot observations of 13 nuclear rings to show an interconnection between the kinematic properties of the rings and their resonant origin. The nuclear rings have regular and symmetric…
Nuclear spirals can provide a wealth of information about the nuclear potential in disc galaxies. They form naturally as a gas response to non-axisymmetry in the gravitational potential, even if the degree of this asymmetry is very small.…
A significant fraction of nearby elliptical galaxies are known to have high density gas disks in their circumnuclear (CN) region (0.1 to a few kpc). Yet, ellipticals, especially luminous ones, show little signs of recent star formation…
The light distribution in the disks of many galaxies is non-axisymmetric or `lopsided' with a spatial extent much larger along one half of a galaxy than the other, as in M101. Recent near-IR observations show that lopsidedness is common.…
Given the dimensions(including thickness) of an axisymmetric galaxy, Newton's law is used in integral form to find the density distributions required to match a wide range of orbital speed profiles. Newton's law is not modified and no…