相关论文: Density-Wave Induced Morphological Transformation …
Deep surveys conducted during the past decades have shown that galaxies in the distant universe are generally of more irregular shapes, and are disky in appearance and in their star formation rate, compared to galaxies in similar…
It is found that a previously thought-to-be well established result of density wave theory, that there is no interaction between a quasi-stationary spiral density wave and the basic state (i.e. the axisymmetric part) of the galactic disk,…
The secular evolution process, which slowly transforms the morphology of a galaxy over its lifetime, could naturally account for observed properties of the great majority of physical galaxies if both stellar and gaseous accretion processes…
It is now a well established fact that galaxies undergo significant morphological transformation during their lifetimes, manifesting as an evolution along the Hubble sequence from the late to the early Hubble types. The physical processes…
We present gravitational N-body simulations of the secular morphological evolution of disk galaxies induced by density wave modes. In particular, we address the demands collective effects place on the choice of simulation parameters, and…
Galaxy evolution is in transition from an early universe dominated by hierarchical clustering to a future dominated by secular processes. These result from interactions involving collective phenomena such as bars, oval disks, spiral…
After a recall of fundamental concepts used in galactic dynamics, we review observational facts as well as results of orbit theory and numerical simulations which suggest long-term evolution of galaxies. Dynamical interactions between…
New observations in favour of a significant role of secular evolution are reviewed: central star formation boosted in pseudo-bulge barred galaxies, relations between bulge and disk, evidence for rejuvenated bulges. Numerical simulations…
Secular evolution gradually shapes galaxies by internal processes, in contrast to early cosmological evolution which is more rapid. An important driver of secular evolution is the flow of gas from the disk into the central regions, often…
Secular evolution is one of the key routes through which galaxies evolve along the Hubble sequence. Not only the disk undergoes morphological and kinematic changes, but also a preexisting classical bulge may be dynamically changed by the…
We combine deep optical and IR photometry for 326 spiral galaxies from two recent galaxy samples and report that the surface brightness profiles of late-type spirals are best fit by two exponentials. Moreover, the ratio of bulge and disk…
We use high resolution collisionless $N$-body simulations to study the secular evolution of disk galaxies and in particular the final properties of disks that suffer a bar and perhaps a bar-buckling instability. Although we find that bars…
Disk galaxies evolve over time through processes that may rearrange both the radial mass profile and the metallicity distribution within the disk. This review of such slow changes is largely, though not entirely, restricted to…
In the current galaxy formation scenarios, two physical phenomena are invoked to build disk galaxies: hierarchical mergers and more quiescent external gas accretion, coming from intergalactic filaments. Although both are thought to play a…
We investigate a model of disk galaxies whereby viscous evolution of the gaseous disk drives material inwards to form a proto-bulge. We start from the standard picture of disk formation through the settling of gas into a dark halo potential…
We review internal processes of secular evolution in galaxy disks, concentrating on the buildup of dense central features that look like classical, merger-built bulges but that were made slowly out of disk gas. We call these pseudobulges.…
I review recent observational progress concerning the evolution of the morphological distribution of galaxies in the rich cluster environment and in the faint field population. By coupling HST imagery with ground-based spectroscopic…
We present a comprehensive series of $N$-body as well as $N$-body + SPH simulations to study the secular evolution of the structure of disk galaxies. Our simulations are organized in a hierarchy of increasing complexity, ranging from…
We have carried out an initial study of a small sample of nearby spiral and barred galaxies with a broad distribution of Hubble types in order to have a first estimate of the magnitude of their secular mass accretion/excretion rates in the…
Using the potential-density phase shift approach developed by the present authors in earlier publications, we estimate the magnitude of radial mass accretion/excretion rates across the disks of six nearby spiral galaxies having a range of…