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Structure formation

About: Structure formation is a research topic. Over the lifetime, 2783 publications have been published within this topic receiving 122490 citations.


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Journal ArticleDOI
02 Jun 2005-Nature
TL;DR: It is shown that baryon-induced features in the initial conditions of the Universe are reflected in distorted form in the low-redshift galaxy distribution, an effect that can be used to constrain the nature of dark energy with future generations of observational surveys of galaxies.
Abstract: The cold dark matter model has become the leading theoretical picture for the formation of structure in the Universe. This model, together with the theory of cosmic inflation, makes a clear prediction for the initial conditions for structure formation and predicts that structures grow hierarchically through gravitational instability. Testing this model requires that the precise measurements delivered by galaxy surveys can be compared to robust and equally precise theoretical calculations. Here we present a simulation of the growth of dark matter structure using 2,1603 particles, following them from redshift z = 127 to the present in a cube-shaped region 2.230 billion lightyears on a side. In postprocessing, we also follow the formation and evolution of the galaxies and quasars. We show that baryon-induced features in the initial conditions of the Universe are reflected in distorted form in the low-redshift galaxy distribution, an effect that can be used to constrain the nature of dark energy with future generations of observational surveys of galaxies.

4,814 citations

Journal ArticleDOI
TL;DR: In this paper, a model for star formation and supernova feedback is proposed to describe the multiphase structure of star-forming gas on scales that are typically not resolved in cosmological simulations.
Abstract: We present a model for star formation and supernova feedback that describes the multiphase structure of star-forming gas on scales that are typically not resolved in cosmological simulations. Our approach includes radiative heating and cooling, the growth of cold clouds embedded in an ambient hot medium, star formation in these clouds, feedback from supernovae in the form of thermal heating and cloud evaporation, galactic winds and outflows, and metal enrichment. Implemented using smoothed particle hydrodynamics, our scheme is a significantly modified and extended version of the grid-based method of Yepes et al., and enables us to achieve a high dynamic range in simulations of structure formation. We discuss properties of the feedback model in detail and show that it predicts a self-regulated, quiescent mode of star formation, which, in particular, stabilizes the star-forming gaseous layers of disc galaxies. The parametrization of this mode can be reduced to a single free quantity that determines the overall time-scale for star formation. We fix this parameter numerically to match the observed rates of star formation in local disc galaxies. When normalized in this manner, cosmological simulations employing our model nevertheless overproduce the observed cosmic abundance of stellar material. We are thus motivated to extend our feedback model to include galactic winds associated with star formation. Using small-scale simulations of individual star-forming disc galaxies, we show that these winds produce either galactic fountains or outflows, depending on the depth of the gravitational potential. In low-mass haloes, winds can greatly suppress the overall efficiency of star formation. When incorporated into cosmological simulations, our combined model for star formation and winds predicts a cosmic star formation density that is consistent with observations, provided that the winds are sufficiently energetic. Moreover, outflows from galaxies in these simulations drive chemical enrichment of the intergalactic medium – in principle, accounting for the presence of metals in the Lyman α forest.

2,050 citations

Journal ArticleDOI
TL;DR: In this article, a model for star formation and supernova feedback that describes the multi-phase structure of star forming gas on scales that are typically not resolved in cosmological simulations is presented.
Abstract: We present a model for star formation and supernova feedback that describes the multi-phase structure of star forming gas on scales that are typically not resolved in cosmological simulations Our approach includes radiative heating and cooling, the growth of cold clouds embedded in an ambient hot medium, star formation in these clouds, feedback from supernovae in the form of thermal heating and cloud evaporation, galactic winds and outflows, and metal enrichment Implemented using SPH, our scheme is a significantly modified and extended version of the grid-based method of Yepes et al (1997), and enables us to achieve high dynamic range in simulations of structure formation We discuss properties of the feedback model in detail and show that it predicts a self-regulated, quiescent mode of star formation, which, in particular, stabilises the star forming gaseous layers of disk galaxies The parameterisation of this mode can be reduced to a single free quantity which determines the overall timescale for star formation We fix this parameter to match the observed rates of star formation in local disk galaxies When normalised in this manner, cosmological simulations nevertheless overproduce the observed cosmic abundance of stellar material We are thus motivated to extend our feedback model to include galactic winds associated with star formation Using small-scale simulations of individual star-forming disk galaxies, we show that these winds produce either galactic fountains or outflows, depending on the depth of the gravitational potential Moreover, outflows from galaxies in these simulations drive chemical enrichment of the intergalactic medium, in principle accounting for the presence of metals in the Lyman alpha forest (abridged)

1,713 citations

Journal ArticleDOI
TL;DR: In this article, the physics of the 21 cm transition were reviewed, focusing on processes relevant at high redshifts, and the insights to be gained from such observations were described.

1,315 citations

Journal ArticleDOI
08 May 2014-Nature
TL;DR: A simulation that starts 12 million years after the Big Bang, and traces 13 billion years of cosmic evolution with 12 billion resolution elements in a cube of 106.5 megaparsecs a side yields a reasonable population of ellipticals and spirals, reproduces the observed distribution of galaxies in clusters and characteristics of hydrogen on large scales, and at the same time matches the ‘metal’ and hydrogen content of galaxies on small scales.
Abstract: Previous simulations of the growth of cosmic structures have broadly reproduced the ‘cosmic web’ of galaxies that we see in the Universe, but failed to create a mixed population of elliptical and spiral galaxies, because of numerical inaccuracies and incomplete physical models. Moreover, they were unable to track the small-scale evolution of gas and stars to the present epoch within a representative portion of the Universe. Here we report a simulation that starts 12 million years after the Big Bang, and traces 13 billion years of cosmic evolution with 12 billion resolution elements in a cube of 106.5 megaparsecs a side. It yields a reasonable population of ellipticals and spirals, reproduces the observed distribution of galaxies in clusters and characteristics of hydrogen on large scales, and at the same time matches the ‘metal’ and hydrogen content of galaxies on small scales. A simulation that starts 12 million years after the Big Bang and traces 13 billion years of cosmic evolution yields a reasonable population of elliptical and spiral galaxies, reproduces the observed distribution of galaxies in clusters and the characteristics of hydrogen on large scales, and at the same time matches the ‘metal’ and hydrogen content of galaxies on small scales. Established cosmological models of galaxy formation and evolution have achieved limited success, failing to create the mixed population of elliptical and spiral galaxies that we observe. A new simulation that makes full use of the latest advances in computing power and algorithmic developments successfully recreates a population of ellipticals and spirals, reproduces the observed distribution of galaxies in clusters, the evolution of dark and visible matter and the characteristics of hydrogen on large scales, at the same time matching the metal (heavier than helium) and hydrogen content of galaxies on small scales. The calculation tracks the build-up of galaxies at unprecedented precision from shortly after the Big Bang until the present day, spanning more than 13 billion years of cosmic evolution.

1,134 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202321
202251
202169
202085
201997
2018100