Related papers: Dating Secular Evolution: Bar Ages from Stellar Ki…
Stellar ages are key for determining the formation history of the Milky Way, but are difficult to measure precisely. Furthermore, methods that use chemical abundances to infer ages may entangle the intrinsic evolution of stars with the…
Bar structures are present in about half of local disk galaxies and play pivotal roles in secular galaxy evolution. Bars impose a non-axisymmetric perturbation to the rotating disk and transport gas inward to feed central starburst and,…
Bars are ubiquitous morphological features in the observed distribution of galaxies. There are similarly many methods for classifying these features and, without a strict theoretical definition or common standard practice, this is often…
Recent studies have revealed that bars can form as early as a few billion years after the Big Bang, already displaying similar characteristics of evolved bars in the Local Universe. Bars redistribute angular momentum across the galaxy,…
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…
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…
Asteroseismology can make a substantial contribution to our understanding of the formation history and evolution of our Galaxy by providing precisely determined stellar properties for thousands of stars in different regions of the Milky…
Age is an important characteristic of a planetary system, but also one that is difficult to determine. Assuming that the host star and the planets are formed at the same time, the challenge is to determine the stellar age. Asteroseismology…
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…
We define a physically-motivated measure for galactic bar length, called the dynamical length. The dynamical length of the bar corresponds to the radial extent of the orbits that are the backbone supporting the bar feature. We propose a…
Accurate and precise stellar ages are best determined for stars which are strongly observationally constrained, that is which are intrinsically oscillating. We review here the seismic diagnostics which are sensitive to stellar ages and…
The age of an individual star cannot be measured, only estimated through mostly model-dependent or empirical methods, and no single method works well for a broad range of stellar types or for a full range in age. This review presents a…
We review current progress in the study of the stellar populations of early-type galaxies, both locally and at intermediate redshifts. In particular, we focus on the ages of these galaxies and their evolution in hopes of determining the…
Recent progress in the understanding of the role of bars and gravitational instabilities in galaxy disks is reviewed. It has been proposed that bars can produce mass transfer towards the center, and progressively metamorphose late-type…
Recent observational constraints restrict the strict applicability of stellar dynamics in spirals to a few rotation periods. However, stellar dynamics concepts such as periodic orbits are invaluable for understanding the various dynamical…
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…
To further enhance our understanding on the formation and evolution of bars in lenticular (S0) galaxies, we are undertaking a detailed photometric and spectroscopic study on a sample of 22 objects. Here we report the results of a 2D…
The details of bulge formation via collapse, mergers, secular processes or their interplay remain unresolved. To start answering this question and quantify the importance of distinct mechanisms, we mapped a sample of three galactic bulges…
To date, Galactic Astronomy has largely concerned itself with astrophysical processes, and with the locations, space motions and compositions of objects. Consider, for example, the elucidation of the components of the Galaxy over the past…
Among the various methods used to age-date stars, methods based on stellar model predictions are widely used, for nearly all kind of stars in large ranges of masses, chemical compositions and evolutionary stages. The precision and accuracy…