Simulations of Large Scale Structure Formation: The Connection to Smaller Scales

2005 ◽  
Vol 216 ◽  
pp. 120-128
Author(s):  
Matthias Steinmetz
Keyword(s):  
Standard Model ◽  
Structure Formation ◽  
Galaxy Formation ◽  
Formation Process ◽  
Large Scale ◽  
Milky Way ◽  
Microwave Background ◽  
The Standard Model ◽  
Dynamical Simulations ◽  
Large Scale Structure Formation

Maps of the cosmos, in particular maps of the cosmic microwave background and of the large scale distribution of galaxies have been crucial ingredients in the development of the standard model of structure formation, sometimes also labeled “concordance model”. This model has proven to be remarkably successful in explaining an impressive array of observations on scales of hundreds of kpc to thousands of Mpc. In this contribution I will attempt to extend those studies to smaller, (sub)galactic scales and will confront detailed gas-dynamical simulations of the formation of individual galaxies with observational data on these scales, reporting some successes and failures of this endeavor. Ongoing surveys that are mapping the distribution of stars in the Milky Way should be able to clearly identify the imprints of the hierarchical galaxy formation process providing an independent check of the validity of the structure formation paradigm.

scholarly journals Of Cosmic Background Anisotropies

1996 ◽  
Vol 168 ◽  
pp. 31-44
Author(s):  
G.F. Smoot
Keyword(s):  
Large Scale ◽  
Thermal Emission ◽  
Big Bang ◽  
Microwave Background ◽  
The Standard Model ◽  
The Big Bang ◽  
The Universe ◽  
Fundamental Physical ◽  
Large Scale Structure Formation

Observations of the Cosmic Microwave Background (CMB) Radiation have put the standard model of cosmology, the Big Bang, on firm footing and provide tests of various ideas of large scale structure formation. CMB observations now let us test the role of gravity and General Relativity in cosmology including the geometry, topology, and dynamics of the Universe. Foreground galactic emissions, dust thermal emission and emission from energetic electrons, provide a serious limit to observations. Nevertheless, observations may determine if the evolution of the Universe can be understood from fundamental physical principles.

scholarly journals The early gaseous and stellar mass assembly of Milky Way-type galaxy halos

2015 ◽  
Vol 11 (S317) ◽  
pp. 235-240
Author(s):  
Gerhard Hensler ◽  
Mykola Petrov
Keyword(s):  
Galaxy Formation ◽  
Large Scale ◽  
Milky Way ◽  
Evolutionary Model ◽  
Satellite System ◽  
Chemical Abundances ◽  
Cosmological Context ◽  
Dynamical Simulations ◽  
Satellite Galaxies ◽  
Mass Assembly

AbstractHow the Milky Way has accumulated its mass over the Hubble time, whether significant amounts of gas and stars were accreted from satellite galaxies, or whether the Milky Way has experienced an initial gas assembly and then evolved more-or-less in isolation is one of the burning questions in modern astronomy, because it has consequences for our understanding of galaxy formation in the cosmological context. Here we present the evolutionary model of a Milky Way-type satellite system zoomed into a cosmological large-scale simulation. Embedded into Dark Matter halos and allowing for baryonic processes these chemo-dynamical simulations aim at studying the gas and stellar loss from the satellites to feed the Milky Way halo and the stellar chemical abundances in the halo and the satellite galaxies.

scholarly journals Maps of the Cosmos: The Cosmic Microwave Background

2005 ◽  
Vol 216 ◽  
pp. 3-17
Author(s):  
Lyman A. Page
Keyword(s):  
Standard Model ◽  
Cosmic Microwave Background ◽  
Large Scale ◽  
Hubble Constant ◽  
Large Scale Structure ◽  
The State ◽  
Microwave Background ◽  
Future Directions ◽  
The Past ◽  
The Standard Model

Since the IAU XXIV meeting in 2000, the CMB anisotropy has matured from being one of a number of cosmological probes to forming the bedrock foundation for what is now the standard model of cosmology. The large advances over the past three years have come from making better and better maps of the cosmos. We review the state of measurements of the anisotropy and outline some of what we have learned since 2000. The recent advancements may be placed roughly into three categories: 1) What we learn from the CMB with minimal input from other cosmic measurements such as the Hubble constant; 2) What we learn from the CMB in combination with other probes of large scale structure; and 3) What we learn by using the CMB as a back light. Future directions are also discussed. It is clear: we have much more to learn from the CMB anisotropy.

scholarly journals Relativistic Cosmology with an Introduction to Inflation

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 276
Author(s):  
Muhammad Zahid Mughal ◽  
Iftikhar Ahmad ◽  
Juan Luis García Guirao
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Large Scale ◽  
Initial Conditions ◽  
Big Bang ◽  
Relativistic Cosmology ◽  
The Standard Model ◽  
Big Bang Model ◽  
The Big Bang ◽  
The Universe

In this review article, the study of the development of relativistic cosmology and the introduction of inflation in it as an exponentially expanding early phase of the universe is carried out. We study the properties of the standard cosmological model developed in the framework of relativistic cosmology and the geometric structure of spacetime connected coherently with it. The geometric properties of space and spacetime ingrained into the standard model of cosmology are investigated in addition. The big bang model of the beginning of the universe is based on the standard model which succumbed to failure in explaining the flatness and the large-scale homogeneity of the universe as demonstrated by observational evidence. These cosmological problems were resolved by introducing a brief acceleratedly expanding phase in the very early universe known as inflation. The cosmic inflation by setting the initial conditions of the standard big bang model resolves these problems of the theory. We discuss how the inflationary paradigm solves these problems by proposing the fast expansion period in the early universe. Further inflation and dark energy in fR modified gravity are also reviewed.

scholarly journals Anisotropy of the Microwave Background and Biased Galaxy Formation

1988 ◽  
Vol 130 ◽  
pp. 43-50
Author(s):  
Nick Kaiser
Keyword(s):  
Galaxy Formation ◽  
Large Scale ◽  
Microwave Background ◽  
Galaxy Clustering ◽  
Clear View ◽  
Hot Gas ◽  
Density Perturbations ◽  
The Universe ◽  
Theoretical Developments

Fluctuations in the microwave background will have been imprinted at z ≃ 1000, when the photons and the plasma decoupled. On angular scales greater than a few degrees these fluctuations provide a clear view of any primordial density perturbations, and therefore a clean test of theories which invoke such fluctuations from which to form the structure we see in the universe. On smaller angular scales the predictions are less certain: reionization of the gas may modify the spectrum of the primordial fluctuations, and secondary fluctuations may be generated.Here I shall review some recent theoretical developments. A brief survey is made of the currently popular theories for the primordial perturbations, with emphasis on the predictions for large scale anisotropy. One major uncetainty in the predictions arises from the normalisation of the fluctuations to e.g. galaxy clustering, and much attention is given to the question of ‘biased’ galaxy formation. The effect of reionization on the primordial fluctuations is discussed, as is the anisotropy generated from scattering off hot gas in clusters, groups and galaxies.

scholarly journals Low-redshift measurement of the sound horizon through gravitational time-delays

2019 ◽  
Vol 632 ◽  
pp. A91 ◽  
Author(s):  
Nikki Arendse ◽  
Adriano Agnello ◽  
Radosław J. Wojtak
Keyword(s):  
Time Delay ◽  
Standard Model ◽  
Percent Level ◽  
Acoustic Oscillations ◽  
Microwave Background ◽  
Direct Measurements ◽  
The Standard Model ◽  
Model Independent ◽  
Competitive Test ◽  
Polynomial Expansions

Context. The matter sound horizon can be infered from the cosmic microwave background within the Standard Model. Independent direct measurements of the sound horizon are then a probe of possible deviations from the Standard Model. Aims. We aim at measuring the sound horizon rs from low-redshift indicators, which are completely independent of CMB inference. Methods. We used the measured product H(z)rs from baryon acoustic oscillations (BAO) together with supernovae Ia to constrain H(z)/H0 and time-delay lenses analysed by the H0LiCOW collaboration to anchor cosmological distances (∝ H0−1). Additionally, we investigated the influence of adding a sample of quasars with higher redshift with standardisable UV-Xray luminosity distances. We adopted polynomial expansions in H(z) or in comoving distances so that our inference was completely independent of any cosmological model on which the expansion history might be based. Our measurements are independent of Cepheids and systematics from peculiar motions to within percent-level accuracy. Results. The inferred sound horizon rs varies between (133 ± 8) Mpc and (138 ± 5) Mpc across different models. The discrepancy with CMB measurements is robust against model choice. Statistical uncertainties are comparable to systematics. Conclusions. The combination of time-delay lenses, supernovae, and BAO yields a distance ladder that is independent of cosmology (and of Cepheid calibration) and a measurement of rs that is independent of the CMB. These cosmographic measurements are then a competitive test of the Standard Model, regardless of the hypotheses on which the cosmology is based.

The TopHat Cosmic Microwave Background Anisotropy Experiment

2005 ◽  
Vol 201 ◽  
pp. 65-70
Author(s):  
Robert F. Silverberg ◽  
Keyword(s):  
Cosmic Microwave Background ◽  
Large Scale ◽  
Background Radiation ◽  
High Sensitivity ◽  
Microwave Background ◽  
Long Duration ◽  
Cosmic Microwave Background Anisotropy ◽  
Microwave Background Radiation ◽  
The Universe ◽  
Large Scale Structure Formation

We have developed a balloon-borne experiment to measure the Cosmic Microwave Background Radiation anisotropy on angular scales from ˜50° down to ˜20′. The instrument observes at frequencies between 150 and 690 GHz and will be flown on an Antarctic circumpolar long duration flight. To greatly improve the experiment performance, the front-end of the experiment is mounted on the top of the balloon. With high sensitivity, broad sky coverage, and well-characterized systematic errors, the results of this experiment can be used to strongly constrain cosmological models and probe the early stages of large-scale structure formation in the Universe.

scholarly journals Large-Scale Structure of the Universe in Unstable Dark Matter Models

1988 ◽  
Vol 130 ◽  
pp. 293-300
Author(s):  
A.G. Doroshkevich ◽  
A.A. Klypin ◽  
M.U. Khlopov
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Large Scale ◽  
Numerical Models ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Microwave Background ◽  
Physical Background ◽  
The Mean ◽  
The Universe

Processes of the formation and the evolution of the large-scale structure are discussed in the framework of unstable dark matter models. Six numerical models are presented. The projected distribution of simulated galaxies on the sky, wedge diagrams, correlation functions and the mean linear scale of voids are presented. Physical background of the hypothesis of unstable particles and possible observational tests are discussed. The level of the microwave background fluctuations is estimated analytically. Special attention is given to late stage of supercluster evolution and galaxy formation.

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