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Recently, the distribution of velocity dispersion as far as 400kpc around red isolated galaxies was derived from statistical studies of satellites in the SDSS (Klypin & Prada 2009). This could help to constrain dark matter models at…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 F. Combes , O. Tiret

The leading tensions to the collisionless cold dark matter (CDM) paradigm are the "small-scale controversies", discrepancies between observations at the dwarf-galactic scale and their simulational counterparts. In this work we consider…

Astrophysics of Galaxies · Physics 2020-11-06 Weishuang Linda Xu , Lisa Randall

$\Lambda$CDM-model predicts an excess of dark halos compared to the observations. The excess is seen from the estimates of the virialized mass inside the Local Supercluster and its surroundings. It is shown that account for cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 E. P. Kurbatov

At large scales and for sufficiently early times, dark matter is described as a pressureless perfect fluid---dust---non-interacting with Standard Model fields. These features are captured by a simple model with two scalars: a Lagrange…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-30 Fabio Capela , Sabir Ramazanov

High resolution dark matter only simulations provide a realistic and fully general means to study the theoretical predictions of cosmological structure formation models for gravitational lensing. Due to the finite number of particles, the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Stefan Rau , Simona Vegetti , Simon D. M. White

The differences between cold (CDM) and warm (WDM) dark matter in the formation of a group of galaxies is examined by running two identical simulations where in the WDM case the initial power spectrum has been altered to mimic a 1keV dark…

We investigate the dynamical state of superclusters in Lambda cold dark matter ($\Lambda$CDM) cosmological models, where the density parameter $\Omega_0=0.2-0.4$ and $\sigma_8$ (the rms fluctuation on the $8h^{-1}$Mpc scale) is $0.7-0.9$.…

Astrophysics · Physics 2009-11-07 Mirt Gramann , Ivan Suhhonenko

By means of the present geometrical and dynamical observational data, it is very hard to establish, from a statistical perspective, a clear preference among the vast majority of the proposed models for the dynamical dark energy and/or…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-07 Tomasz Denkiewicz , Vincenzo Salzano

We present a study of numerical effects in dissipationless cosmological simulations. The numerical effects are evaluated and studied by comparing results of a series of 64^3-particle simulations of varying force resolution and number of…

Astrophysics · Physics 2009-10-31 Alexander Knebe , Andrey V. Kravtsov , Stefan Gottloeber , Anatoly Klypin

We show that discreteness effects related to classical two-body relaxation produce spurious heating of the gaseous component in numerical simulations of galaxy formation. A simple analytic model demonstrates that this artificial heating…

Astrophysics · Physics 2015-06-24 Matthias Steinmetz , Simon D. M. White

We show how knowledge of the cold dark matter (CDM) density can be used, in conjunction with measurements of the parameters of a scenario for beyond the Standard Model (BSM) physics, to provide information about the evolution of the…

High Energy Physics - Phenomenology · Physics 2018-10-24 A. Arbey , J. Ellis , F. Mahmoudi , G. Robbins

All observational evidence for dark matter and dark energy is so far exclusively gravitational. Hence, the dark sector may be equivalently described by a theory of the spacetime metric whose dynamics is affected by interactions with an…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-10 Santiago Agüí Salcedo , Thomas Colas , Lennard Dufner , Enrico Pajer

Dark matter (DM) with self-interactions is a promising solution for the small-scale problems of the standard cosmological model. Here we perform the first cosmological simulation of frequent DM self-interactions, corresponding to…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-07 Moritz S. Fischer , Marcus Brüggen , Kai Schmidt-Hoberg , Klaus Dolag , Felix Kahlhoefer , Antonio Ragagnin , Andrew Robertson

I argue that the cold dark matter (CDM) model requires that even within a few kpc of the center of a galactic halo a significant fraction (greater than a few percent) of the surface density is contained in substructures with masses > 10^3…

Astrophysics · Physics 2007-05-23 R. Benton Metcalf

We have developed a machine learning algorithm capable of detecting ``out-of-domain data'' for trustworthy cosmological inference. By using data from two separate suites of cosmological simulations, we show that our algorithm is able to…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-21 Ethan Tregidga , David Harvey , Luca Biggio , Felix Vecchi

Self-Interacting Dark Matter (SIDM) has long been proposed as a solution to small scale problems posed by standard Cold Dark Matter (CDM). We use numerical simulations to study the effect of dark matter interactions on the morphology of…

Astrophysics of Galaxies · Physics 2018-06-15 Lucas F. Secco , Amanda Farah , Bhuvnesh Jain , Susmita Adhikari , Arka Banerjee , Neal Dalal

The suppression of cosmological structure at small scales is a key signature of dark matter (DM) produced via freeze-in in the low-mass regime. We present a comprehensive analysis of its impact, incorporating recent constraints from Milky…

High Energy Physics - Phenomenology · Physics 2025-12-12 Francesco D'Eramo , Alessandro Lenoci , Ariane Dekker

We investigate the wave-optical light scattering properties of deformed thin circular films of constant thickness using the discrete-dipole approximation. Effects on the intensity distribution of the scattered light due to different…

Optics · Physics 2020-10-09 Hannu Parviainen , Kari Lumme

Contrary to recent claims in the literature, Newtonian N-body simulations of collisionless Dark Matter in a LambdaCDM background are compatible with general relativity and are not invalidated by general relativistic effects at the linear…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-02 Thomas Haugg , Stefan Hofmann , Michael Kopp

Celestial capture of dark matter provides a useful handle for constraining its particulate properties. The capture formalism is sensitive to the phase space distribution of dark matter in the vicinity of the celestial object. This article…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-21 Debajit Bose , Sambo Sarkar