Related papers: Galaxy Morphology
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…
Galaxy morphology is a product of how galaxies formed, how they interacted with their environment, how they were influenced by internal perturbations, AGN, and dark matter, and of their varied star formation histories. This article reviews…
Secular evolution and fueling is driven by bars in spiral galaxies, and the related dynamical processes are reviewed. It is shown that gravity torques dominate over viscous torques, and produce gas infall to the center. In this infall, the…
Galaxy disks evolve through angular momentum transfers between sub-components, like gas, stars, or dark matter halos, through non axi-symmetric instabilities. The speed of this evolution is boosted in presence of a large fraction of cold…
Bulges are of different types, morphologies and kinematics, from pseudo-bulges, close to disk properties (Sersic index, rotation fraction, flatenning), to classical de Vaucouleurs bulges, close to elliptical galaxies. Secular evolution and…
Self-gravitating systems evolve toward the most tightly bound configuration that is reachable via available evolution processes. The inner parts shrink and the outer parts expand, provided that some physical process transports energy or…
The secular evolution process which slowly transforms the morphology of a given galaxy over its lifetime through mostly internal dynamical mechanisms could naturally account for most of the observed properties of physical galaxies (Zhang…
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…
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…
Today we have numerous evidences that spirals evolve dynamically through various secular or episodic processes, such as bar formation and destruction, bulge growth and mergers, sometimes over much shorter periods than the standard galaxy…
From this vast subject, I will pick out and review three specific topics, namely the formation and evolution of bars, the formation of bulges, and the evolution during multiple major mergers. Bars form naturally in galactic discs. Their…
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…
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…
The study of the morphology of galaxies is important in order to understand the formation and evolution of galaxies and their sub-components as a function of luminosity, environment, and star-formation and galaxy assembly over cosmic time.…
Through vertical resonances, bars can produce pseudo-bulges, within secular evolution. Bulges and pseudo-bulges have doubled their mass since z=1. The frequency of bulge-less galaxies at z=0 is difficult to explain, especially since clumpy…
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…
Simulations and observations of galactic bars suggest they do not commonly evolve into bulges, although it is possible that the earliest bars formed bulges long ago, when galaxies were smaller, denser, and had more gas. The most highly…
Stellar bars are important internal drivers of secular evolution in disk galaxies. Using a sample of nearby spiral galaxies with weak and strong bars, we explore the relationships between the star formation feature and stellar bars in…
Dynamical evolution of spiral galaxies is strongly dependent on non-axisymmetric patterns that develop from gravitational instabilities, either spontaneously or externally triggered. Some evolutionary sequences are described through which a…