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Several extensions of the standard cosmological model include scalar fields as new degrees of freedom in the underlying gravitational theory. A particular class of these scalar field theories include screening mechanisms intended to hide…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-04 Claudio Llinares , David F. Mota , Hans A. Winther

We develop a new method to reconstruct the cosmic density field from the distribution of dark matter haloes above a certain mass threshold. Our motivation is that well-defined samples of galaxy groups/clusters, which can be used to…

Astrophysics · Physics 2009-11-13 H. Y. Wang , H. J. Mo , Y. P. Jing , Y. C. Guo , Frank C. van den Bosch , X. H. Yang

The structural and dynamic properties of the dark matter halos, though an important ingredient in understanding large-scale structure formation, require more conservative particle resolution than those required by halo mass alone in a…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-23 Sujatha Ramakrishnan , Premvijay Velmani

We show that the two basic assumptions of the model recently proposed by Manrique and coworkers for the universal density profile of cold dark matter (CDM) halos, namely that these objects grow inside out in periods of smooth accretion and…

Recent work has highlighted the potentially detectable gravitational-lensing effect of neutrino halos on cosmic-microwave-background (CMB) fluctuations with upcoming instruments like SO, CMB-S4, and CMB-HD. Accurate modeling of…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-14 Keduse Worku , Nashwan Sabti , Marc Kamionkowski

Adaptive SPH and N-body simulations were carried out to study the effect of gasdynamics on the structure of dark matter halos that result from the gravitational instability and fragmentation of cosmological pancakes. Such halos resemble…

Astrophysics · Physics 2007-05-23 Marcelo Alvarez , Paul R. Shapiro , Hugo Martel

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

We present an algorithm for quickly generating multiple realizations of N-body simulations to be used, for example, for cosmological parameter estimation from surveys of large-scale structure. Our algorithm uses a new method to resample the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Michael D. Schneider , Shaun Cole , Carlos S. Frenk , Istvan Szapudi

We study the evolution of the halo-halo correlation function and bias in a LCDM model using very high-resolution N-body simulations. The high force and mass resolution allows dark matter (DM) halos to survive in the tidal fields in…

Astrophysics · Physics 2007-05-23 Andrey Kravtsov , Anatoly Klypin , Pedro Colin , Alexei Khokhlov

We study the density profile of a dwarf halo in the decaying dark matter (DDM) cosmology, using a new algorithm that resolves halo density profiles down to the innermost $700$ pc robustly with high efficiency. Following Schwarzschild's…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-20 Jianxiong Chen , M. -C. Chu

We present new results characterizing cosmological shocks within adaptive mesh refinement N-Body/hydrodynamic simulations that are used to predict non-thermal components of large-scale structure. This represents the first study of shocks…

We present and test a new halo finder based on the spherical overdensity (SO) method. This new adaptive spherical overdensity halo finder (ASOHF) is able to identify dark matter haloes and their substructures (subhaloes) down to the scales…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Susana Planelles , Vicent Quilis

We train graph neural networks on halo catalogues from Gadget N-body simulations to perform field-level likelihood-free inference of cosmological parameters. The catalogues contain $\lesssim$5,000 halos with masses $\gtrsim…

We study the concentration of dark matter halos and its evolution in N-body simulations of the standard LCDM cosmology. The results presented in this paper are based on 4 large N-body simulations with about 10 billion particles each: the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Francisco Prada , Anatoly A. Klypin , Antonio J. Cuesta , Juan E. Betancort-Rijo , Joel Primack

We study the effects of mass and force resolution on the density profiles of galaxy-size Cold Dark Matter (CDM) halos in a flat, low-density cosmological model with vacuum energy. We show thatalthough increasing the mass and force…

Astrophysics · Physics 2008-11-26 Anatoly Klypin , Andrey V. Kravtsov , James Bullock , Joel Primack

Self-interacting dark matter (SIDM) theory predicts that dark matter halos experience core-collapse, a process where the halo's inner region rapidly increases in density and decreases in size. The N-body simulations used to study this…

The gravitational lensing properties of cosmological halos depend upon the mass distribution within each halo. The description of halos as nonsingular, truncated isothermal spheres, a particular solution of the isothermal Lane-Emden…

Astrophysics · Physics 2007-05-23 Hugo Martel , Paul R. Shapiro

Accurate predictions of the abundance and clustering of dark matter haloes play a key role in testing the standard cosmological model. Here, we investigate the accuracy of one of the leading methods of connecting the simulated dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-15 Anatoly Klypin , Francisco Prada , Gustavo Yepes , Steffen Hess , Stefan Gottlober

We report a series of high-resolution cosmological N-body simulations designed to explore the formation and properties of dark matter halos with masses close to the damping scale of the primordial power spectrum of density fluctuations. We…

Astrophysics · Physics 2009-11-13 P. Colin , O. Valenzuela , V. Avila-Reese

We present a detailed description and validation of our massively-parallel update to the mass-Peak Patch method, a fully predictive initial-space algorithm to quickly generate dark matter halo catalogues in very large cosmological volumes.…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-05 George Stein , Marcelo A. Alvarez , J. Richard Bond