Related papers: Lost in secular evolution: the case of a low mass …
Close examination of so-called "pseudobulges" in several early-type disk galaxies indicates that they are actually composite structures consisting of both a flattened, kinematically cool disklike structure ("disky pseudobulge") and a…
Bulges in spiral galaxies have been supposed to be classified into two types: classical bulges or pseudobulges. Classical bulges are thought to form by galactic merger with bursty star formation, whereas pseudobulges are suggested to form…
Most giant spiral galaxies have pseudo or disk-like bulges that are considered to be the result of purely secular processes. This may challenge the hierarchical scenario predicting about one major merger per massive galaxy ($>$$3\times…
Evolution of stellar bars in disk galaxies is accompanied by dynamical instabilities and secular changes. Following the vertical buckling instability, the bars are known to weaken dramatically and develop a pronounced boxy/peanut shape when…
After presenting three ways of defining a bulge component in disc galaxies, we introduce the various types of bulges, namely the classical bulges, the boxy/peanut bulges and the disc-like bulges. We then discuss three specific topics linked…
We have done a detailed study on the structural and kinematical properties of lenticular and early- and late-type spiral galaxies with bars, aiming to explore the formation and evolution processes of stellar bars in galaxies, and their…
The assembly of the Milky Way bulge is an old topic in astronomy, one now in a period of renewed and rapid development. The dominant scenario for bulge formation is that of the Milky Way as a nearly pure disk galaxy, with the inner disk…
The Milky Way is a barred galaxy whose central bulge has a box/peanut shape and consists of multiple stellar populations with different orbit distributions. This review describes dynamical and chemo-dynamical equilibrium models for the…
Boxy and peanut-shaped bulges are seen in about half of edge-on disc galaxies. Comparisons of the photometry and major-axis gas and stellar kinematics of these bulges to simulations of bar formation and evolution indicate that they are bars…
It has been suggested that the peanut-shaped bulges seen in some edge-on disk galaxies are produced when bars in these galaxies buckle. This paper reviews the modelling which seeks to show how bars buckle, and I present a very simple new…
More than half of nearby disc galaxies have pseudobulges instead of classical bulges that are though to be end-products of galaxy mergers. Pseudobulges are presumed to develop overtime as a result of secular evolution of galaxy discs. We…
A new idea is proposed for the origin of bulges in spiral galaxies. Numerical simulations for the protogalactic collapse suggest strongly that galactic bulges have been assembled from massive clumps formed in the galactic disks in their…
Barred galaxies have interesting morphological features whose presence and properties set constraints on galactic evolution. Here we examine barlenses, i.e. lens-like components whose extent along the bar major axis is shorter than that of…
It is widely accepted that within the framework of LCDM a significant fraction of giant-disk galaxies has recently experienced a violent galactic merger. We present numerical simulations of such major mergers of gas-rich pure disk galaxies,…
I use Spitzer 3.6-8.0 \mu m color profiles to compare the radial structure of star formation in pseudobulges and classical bulges. Pseudobulges are ``bulges'' which form through secular evolution, rather than mergers. In this study,…
Major-axis long-slit stellar kinematics was obtained for 30 edge-on spiral galaxies, 24 with a boxy/peanut-shaped (B/PS) bulge. B/PS bulges are present in >45% of highly inclined systems and much work suggests that they are the edge-on…
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…
Bulges in spiral galaxies have been supposed to be classified into two types: classical bulges or pseudobulges. Classical bulges are thought to form by galactic merger with bursty star formation, whereas pseudobulges are suggested to form…
The Milky Way bulge offers a unique opportunity to investigate in detail the role that different processes such as dynamical instabilities, hierarchical merging, and dissipational collapse may have played in the history of the Galaxy…
The internal evolution of disk galaxies like the Milky Way are driven by non-axisymmetries (bars) and the implied angular momentum transfer of the matter; baryons are essentially driven inwards to build a more concentrated disk. This mass…