Galaxy Dynamics: Secular Evolution and Accretion
نویسندگان
چکیده
منابع مشابه
Secular Evolution of Galaxy Morphologies
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 age of 10− 15 Gyr. This, coupled to the known properties of the Hubble sequence, leads to a unique sense of evolution: from Sm to Sa. Linking this to the known...
متن کاملGalaxy Scaling Relations as a Result of Secular Evolution
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 2003a). As an emerging paradigm for galaxy evolution, its dynamical foundations had been established in the past few years (Zhang 1996, 1998, 1999). In this pa...
متن کاملSecular instability in quasi-viscous disc accretion
A first-order correction in the α-viscosity parameter of Shakura & Sunyaev has been introduced in the standard inviscid and thin accretion disc. A linearised time-dependent perturbative study of the stationary solutions of this “quasi-viscous” disc leads to the development of a secular instability on large spatial scales. This qualitative feature is equally manifest for two different types of p...
متن کاملSecular Evolution of Disks
It is found that a previously thought-to-be well established result of density wave theory, that there is no interaction between a quasistationary spiral density wave and the basic state (i.e. the axisymmetric part) of the galactic disk, is in fact false. When solved as a nonlinear and globally self-consistent problem, the presence of non-axisymmetric patterns such as spirals or bars is shown t...
متن کاملSecular evolution in galaxies
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 have shown that secular evolution can occur through a cycle of bar formation and destruction, in which the gas plays a major role. Since bars are weakened or de...
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ژورنال
عنوان ژورنال: Proceedings of the International Astronomical Union
سال: 2010
ISSN: 1743-9213,1743-9221
DOI: 10.1017/s1743921311017522