Related papers: The Bulge/Disk Connection in Late-type Spirals
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…
Spiral galaxies have most of their stellar mass in a large rotating disk, and only a modest fraction in a central spheroidal bulge. This poses a major challenge for cosmological models of galaxy formation. Galaxies form at the centre of…
Classical bulges and stellar bars are common features in disk galaxies and serve as key tracers of galactic evolution. Angular momentum exchange at bar resonances drives secular morphological changes throughout the disk, including bar…
We present Ha integral field spectroscopy of well resolved, UV/optically selected z~2 star-forming galaxies as part of the SINS survey with SINFONI on the ESO VLT. Our laser guide star adaptive optics and good seeing data show the presence…
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…
Historically, galactic bulges are thought to be elliptical galaxy-like objects sitting in the middle of a generally larger disk. There are, however, more and more claims that some bulges are much more similar to disks. John Kormendy has…
Gas-rich disks in the early universe are highly turbulent and have giant star-forming clumps. Models suggest the clumps form by gravitational instabilities, and if they resist disruption by star formation, then they interact, lose angular…
A tantalizing enigma in extragalactic astronomy concerns the chronology and driving mechanisms of the build-up of late-type galaxies (LTGs). The standard scenario envisages two formation routes, with classical bulges (CBs) assembling first…
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…
The formation of late-type galaxies has traditionally been described via two pathways: one producing pressure-supported classical bulges, the other rotationally supported pseudo-bulges. Early studies relied on photometric decompositions…
In this paper, we present three qualitatively different scenarios for bulge formation: a secular evolution model in which bulges form after disks and undergo several central starbursts, a primordial collapse model in which bulges and disks…
Bulges are a major galaxy component in the nearby universe, and are one of the primary features that differentiates and defines galaxies. The origin of bulges can be directly probed in part by examining distant galaxies to search for high…
The currently discussed theories of bulge formation are reviewed, including the primordial scenario, where bulges form rapidly and then accrete disks, the secular scenario, where bulges are formed by dynamical evolution of disks through…
We present a theoretical model for the evolution of mass, angular momentum and size of galaxy disks and bulges, and we implement it into the semi-analytic galaxy formation code SAGE. The model follows both secular and violent evolutionary…
The existence of a classical bulge in disk galaxies holds important clue to the assembly history of galaxies. Finding observational evidence of very low mass classical bulges particularly in barred galaxies including our Milky Way, is a…
We examine whether early-type galaxies in clusters may have evolved from later types by the fading of their disks (e.g., as a result of ram-pressure stripping or strangulation) or by enhancement of the bulge luminosity (e.g., due to tidal…
We suggest that the bulge-to-disc ratios of spiral galaxies are primarily determined by the angular momenta of their host haloes predicted in current hierarchical clustering models for structure formation. Gas with low specific angular…
We investigate the stellar disk properties of a sample of 19 nearby spiral galaxies with low inclination and late Hubble type (Scd or later). We combine our high-resolution HST I-band observations with existing ground-based optical images…
We made a detailed analysis of the sample of 39 cluster spiral galaxies of various types observed at H$\alpha$ wavelength by Amram et al. (1992 to 1996), with a scanning Fabry-Perot. We plotted the outer gradient of their rotation curves as…
Observations reveal that mature spiral galaxies consist of stars, gases and plasma approximately distributed in a thin disk of circular shape, usually with a central bulge. The rotation velocities quickly increase from the galactic center…