Simulating Large-scale Structure

The large-scale structure of the Universe formed from initially small perturbations in the cosmic density field, leading to galaxy clusters with up to 10^15 Msun at the present day. Here, we review the formation of structures in the Universe, considering the first primordial galaxies and the most massive galaxy clusters as extreme cases of structure formation where fundamental processes such as gravity, turbulence, cooling and feedback are particularly relevant. The first non...

Simulations of large-scale structure in the universe have played a vital role in observational cosmology since 1980's in particular. Their important role will definitely continue to be true in the 21st century. Rather the requirements for simulations in the precision cosmology era will become more progressively demanding; they are supposed to fill the missing link in an accurate and reliable manner between the ``initial'' condition at z=1000 revealed by WMAP and the galaxy/qu...

For the first time, the combination of semi-analytic modelling of galaxy formation and N-body simulations of cosmic structure formation enables us to model, at the same time, both the photometric and the clustering properties of galaxies. Two Cold Dark Matter Universes provide a reasonable fit to the observed properties of galaxies, groups and clusters, including luminosities, colours, density and velocity biases. We show how the properties of galaxies and groups on small sca...

In the study of the process of cosmic structure formation numerical simulations are crucial tools to interface observational data to theoretical models and to investigate issues otherwise unexplored. Enormous advances have been achieved in the last years thanks to the availability of sophisticated codes, now allowing to tackle the problem of cosmic structure formation and subsequent evolution by covering larger and larger dynamical ranges. Moreover, computational cosmology is...

Cosmological N-Body simulations have become an essential tool for studying formation of large scale structure. These simulations are computationally challenging even though the available computing power gets better every year. A number of efficient algorithms have been developed to run large simulations with better dynamic range and resolution. We discuss key algorithms in this review, focusing on techniques used and their efficacy. N-Body simulations solve a model that is an...

The gravitationally-driven evolution of cold dark matter dominates the formation of structure in the Universe over a wide range of length scales. While the longest scales can be treated by perturbation theory, a fully quantitative understanding of nonlinear effects requires the application of large-scale particle simulation methods. Additionally, precision predictions for next-generation observations, such as weak gravitational lensing, can only be obtained from numerical sim...

We describe cosmological simulation techniques and their application to studies of cosmic structure formation, with particular attention to recent hydrodynamic simulations of structure in the high redshift universe. Collisionless N-body simulations with Gaussian initial conditions produce a pattern of sheets, filaments, tunnels, and voids that resembles the observed large scale galaxy distribution. Simulations that incorporate gas dynamics and dissipation form dense clumps of...

Cosmic structure simulations have improved enormously over the past decade, both in terms of the resolution which can be achieved, and with the addition of hydrodynamic and other techniques to formerly purely gravitational methods. This is an informal, and perhaps idiosyncratic, overview of the state and progress of cosmological simulations over this period. I will discuss the strategies that are used to understand cosmic structure formation and the requirements of a succes...

Clusters of galaxies are studied from a theoretical point of view, comparing with observational results whenever possible. The problem is approached both analytically as well as by means of high-resoultion numerical simulations. The dark matter halo, the hot intracluster gas, and the stellar component are investigated separately. Numerical clusters are consistent with a relatively simple scenario, in which these objects form around local maxima of the primordial density field...

The development of numerical N -body simulations have allowed to study formation process and evolution of galaxies at different scales. This paper presents the fundamental concepts of N-body systems applied to the cosmological evolution of the $\Lambda$-Cold Dark Matter ($\Lambda$CDM) model. In order to perform structure formation in the Universe, we provide an introduction to the basic equations and their implementation on the GADGET-2 software. We also present a simple guid...