Related papers: Galaxy Formation: Merger vs Gas Accretion
Polar ring galaxies are flattened stellar systems with an extended ring of gas and stars rotating in a plane almost perpendicular to the central galaxy. We show that their formation can occur naturally in a hierarchical universe where most…
Evidence for gas accretion onto galaxies can be found throughout the universe. In this chapter, I summarize the direct and indirect signatures of this process and discuss the primary sources. The evidence for gas accretion includes the star…
This paper discusses how cosmic gas accretion controls star formation, and summarizes the physical properties expected for the cosmic gas accreted by galaxies. The paper also collects observational evidence for gas accretion sustaining star…
Cosmology requires at least half of the baryons in the Universe to be in the intergalactic medium, much of which is believed to form hot coronae around galaxies. Star-forming galaxies must be accreting from their coronae. HI observations of…
Cosmological simulations of galaxy formation appear to show a two-phase character with a rapid early phase at z>2 during which in-situ stars are formed within the galaxy from infalling cold gas followed by an extended phase since z<3 during…
Cosmological simulations predict that early-type galaxies (ETGs) are the results of extended mass accretion histories. The latter are characterized by different numbers of mergers, mergers mass ratios and gas fractions, and timing.…
The discovery of a population of massive, compact and quiescent early-type galaxies has changed the view on plausible formation scenarios for the present day population of elliptical galaxies. Traditionally assumed formation histories…
Mass accretion is the key factor for evolution of galaxies. It can occur through secular evolution, when gas in the outer parts is driven inwards by dynamical instabilities, such as spirals or bars. This secular evolution proceeds very…
Galaxies with Milky Way-like stellar masses have a wide range of bulge and black hole masses; in turn, these correlate with other properties such as star formation history. While many processes may drive bulge formation, major and minor…
The satellites of the Milky Way and Andromeda represent the smallest galaxies we can observe in our Universe. In this series of papers we aim to shed light on their formation and evolution using cosmological hydrodynamical simulations. In…
We use hydrodynamic simulations to examine how the baryonic components of galaxies are assembled, focusing on the relative importance of mergers and smooth accretion in the formation of ~L_* systems. In our primary simulation, which models…
In models of galaxy formation in a hierarchical Universe, elliptical galaxies form through the merging of smaller disk systems. These models yield a number of testable predictions if reliable techniques for determining the relative ages and…
The formation of star clusters involves the growth of smaller, gas-rich subclusters through accretion of gas from the giant molecular cloud within which the subclusters are embedded. The two main accretion mechanisms responsible for this…
A simple, 1-equation, galaxy formation model is applied to both the halo merger tree derived from a high-resolution dissipationless cosmological simulation and to 1/4 million Monte-Carlo halo merger trees. The galaxy formation model…
The physical phenomena contributing to the galaxy growth can be tested all the way to z= 1. Galaxy mass, extinction, star formation and gas metal abundance can be measured in a robust way, as well as the distribution of the galaxy…
In planetary science, accretion is the process in which solids agglomerate to form larger and larger objects and eventually planets are produced. The initial conditions are a disc of gas and microscopic solid particles, with a total mass of…
We introduce a toy model that describes (in a single equation) the mass in stars as a function of halo mass and redshift. Our model includes the suppression of gas accretion from gravitational shock heating and AGN jets mainly for M_halo >…
Although the basic physics of star formation is classical, numerical simulations have yielded essential insights into how stars form. They show that star formation is a highly nonuniform runaway process characterized by the emergence of…
In the two-phase scenario of galaxy formation, a galaxy's stellar mass growth is first dominated by in-situ star formation, and subsequently by accretion. We analyse the radial distribution of the accreted stellar mass in ~500 galaxies from…
We discuss how the conditions at high redshift differ from those at low redshift, and what the impact is on the galaxy population. We focus in particular on the role of gaseous dissipation and its impact on sustaining high star formation…