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Related papers: Machine learning cosmological structure formation

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It is well established from cosmological simulations that dark matter haloes are not precisely self-similar and an additional parameter, beyond their concentration, is required to accurately describe their spherically-averaged mass density…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Shaun T. Brown , Ian G. McCarthy , Sam G. Stafford , Andreea S. Font

An analytical model is presented for the postcollapse equilibrium structure of virialized objects which condense out of a low-density cosmological background universe, either matter-dominated or flat with a cosmological constant. This…

Astrophysics · Physics 2009-11-06 Ilian T. Iliev , Paul R. Shapiro

Thanks to the ever increasing computational power and the development of more sophisticated algorithms, numerical N-body simulations are now uncovering several phenomenological relations between the physical properties of dark matter haloes…

Astrophysics · Physics 2009-11-13 Yago Ascasibar , Stefan Gottloeber

We develop a machine learning approach to reconstructing the cosmological initial conditions from late-time dark matter halo number density fields in redshift space, with the goal of improving sensitivity to cosmological parameters, and in…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-15 Jelte Bottema , Thomas Flöss , P. Daniel Meerburg

Both simulation and observational data have shown that the spin and shape of dark matter halos are correlated with their nearby large-scale environment. As structure formation on different scales is strongly coupled, it is trick to…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-27 Hou-Zun Chen , Xi Kang , Peng Wang , Noam I. Libeskind , Yu Luo

Cosmologists aim to model the evolution of initially low amplitude Gaussian density fluctuations into the highly non-linear "cosmic web" of galaxies and clusters. They aim to compare simulations of this structure formation process with…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-05 Renan Alves de Oliveira , Yin Li , Francisco Villaescusa-Navarro , Shirley Ho , David N. Spergel

We use two cosmological simulations of structure formation to study the conditions under which dark matter haloes emerge from the linear density field. Our analysis focuses on matching sites of halo collapse to local density maxima, or…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Aaron D. Ludlow , Cristiano Porciani

The balance of evidence indicates that individual galaxies and groups or clusters of galaxies are embedded in enormous distributions of cold, weakly interacting dark matter. These dark matter 'halos' provide the scaffolding for all luminous…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-26 James E. Taylor

Next-generation surveys will provide photometric and spectroscopic data of millions to billions of galaxies with unprecedented precision. This offers a unique chance to improve our understanding of the galaxy evolution and the unresolved…

The nature of structure formation around the particle free streaming scale is still far from understood. Many attempts to simulate hot, warm, and cold dark matter cosmologies with a free streaming cutoff have been performed with…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Aurel Schneider , Robert E. Smith , Darren Reed

We investigate machine learning (ML) techniques for predicting the number of galaxies (N_gal) that occupy a halo, given the halo's properties. These types of mappings are crucial for constructing the mock galaxy catalogs necessary for…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Xiaoying Xu , Shirley Ho , Hy Trac , Jeff Schneider , Barnabas Poczos , Michelle Ntampaka

We describe an algorithm for identifying ellipsoidal haloes in numerical simulations, and quantify how the resulting estimates of halo mass and shape differ with respect to spherical halo finders. Haloes become more prolate when fit with…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-19 Giulia Despali , Giuseppe Tormen , Ravi K. Sheth

Although high-resolution N-body simulations make robust empirical predictions for the density distribution within cold dark matter halos, these studies have yielded little physical insight into the origins of the distribution. We…

Astrophysics · Physics 2008-11-26 Liliya L. R. Williams , Arif Babul , Julianne J. Dalcanton

We use the extended Press-Schechter formalism to investigate the rate at which cold dark matter haloes accrete mass. We discuss the shortcomings of previous methods that have been used to compute the mass accretion histories of dark matter…

Astrophysics · Physics 2008-11-26 Frank C. van den Bosch

A modified version of the extended Press-Schechter model for the growth of dark-matter haloes was introduced in two previous papers with the aim at explaining the mass-density relation shown by haloes in high-resolution cosmological…

Astrophysics · Physics 2009-11-07 A. Raig , G. Gonzalez-Casado , E. Salvador-Sole

If the concordance $\Lambda$CDM model is a true description of the universe, it should also properly predict the properties and structure of dark matter haloes, where galaxies are born. Using N-body simulations with a broad scale of mass…

Astrophysics · Physics 2016-08-15 P. Nurmi , P. Heinämäki , E. Saar , M. Einasto , J. Holopainen , V. J. Martínez , J. Einasto

Associating the formation sites of haloes with the maxima of the smoothed linear density field, we present non-perturbative predictions for the Lagrangian and evolved halo correlation functions that are valid at all separations. In…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-05 Tobias Baldauf , Sandrine Codis , Vincent Desjacques , Christophe Pichon

The standard cold dark matter (CDM) model predicts too many and too dense small structures. We consider an alternative model that the dark matter undergoes two-body decays with cosmological lifetime $\tau$ into only one type of massive…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-04 Dalong Cheng , M. -C. Chu , Jiayu Tang

The mean matter density within the turnaround radius, which is the boundary that separates a nonexpanding structure from the Hubble flow, was recently proposed as a novel cosmological probe. According to the spherical collapse model, the…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-14 Giorgos Korkidis , Vasiliki Pavlidou , Konstantinos Tassis

We present a novel method of robust probabilistic cosmic web particle classification in three dimensions using a supervised machine learning algorithm. Training data was generated using a simplified $\Lambda$CDM toy model with…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-10 Brandon Buncher , Matias Carrasco Kind