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We examine the proposal that a model of the large-scale matter distribution consisting of randomly placed haloes with power-law profile, as opposed to a fractal model, can account for the observed power-law galaxy-galaxy correlations. We…

Astrophysics · Physics 2008-11-26 Jose Gaite

We have made a detailed comparison of the results of large N-body simulations with the analytical description of the merging histories of dark matter halos presented in Lacey & Cole 1993, which is based on an extension of the Press-…

Astrophysics · Physics 2015-06-24 Cedric Lacey , Shaun Cole

Hierarchical models of structure formation predict that dark matter halo assembly histories are characterised by episodic mergers and interactions with other haloes. An accurate description of this process will provide insights into the…

Astrophysics of Galaxies · Physics 2019-11-26 Rhys J. J. Poulton , Chris Power , Aaron S. G. Robotham , Pascal J. Elahi

We present a new method for calculating the merger history of matter halos in hierarchical clustering cosmologies. The linear density field is smoothed on a range of scales, these are then ordered in decreasing density and a merger tree…

Astrophysics · Physics 2015-06-24 Domingos D. C. Rodrigues , Peter A. Thomas

We derive an analytic formula of genus for dark matter halos assuming that the primordial mass density field obeys the random-Gaussian statistics. In particular, we for the first time take account of the nonlinear nature of the halo…

Astrophysics · Physics 2009-11-06 Chiaki Hikage , Atsushi Taruya , Yasushi Suto

The concentration of dark matter haloes is closely linked to their mass accretion history. We utilize the halo mass accretion histories from large cosmological N-body simulations as inputs for our neural networks, which we train to predict…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-29 Tianchi Zhang , Tianxiang Mao , Wenxiao Xu , Guan Li

The relation between halo mass, M, and concentration, c, is a critical component in our understanding of the structure of dark matter halos. While numerous models for this relation have been proposed, almost none of them attempt to derive…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-31 Benedikt Diemer , Michael Joyce

Hierarchical structure formation theory is based on the notion that mergers drive galaxy evolution, so a considerable framework of semi-analytic models and N-body simulations has been constructed to calculate how mergers transform a growing…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Manodeep Sinha , Kelly Holley-Bockelmann

Using high resolution DM simulations we study the shape of dark matter halos. Halos become more spherical with decreasing mass. This trend is even more pronounced for the inner part of the halo. Angular momentum and shape are correlated.…

Astrophysics · Physics 2009-11-11 Stefan Gottloeber , Victor Turchaninov

We build a simple analytical model for the bias of dark matter halos that applies to objects defined by an arbitrary density threshold, $200\leq\deltas\leq 1600$, and that provides accurate predictions from low-mass to high-mass halos. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Patrick Valageas

Merger trees follow the growth and merger of dark-matter haloes over cosmic history. As well as giving important insights into the growth of cosmic structure in their own right, they provide an essential backbone to semi-analytic models of…

It has recently been shown that relaxed spherically symmetric dark matter halos develop from the inside out, by permanently adapting their inner structure to the boundary conditions imposed by the current accretion rate. Such a growth…

Spherical density profiles and specific angular momentum profiles of Dark Matter halos found in cosmological N-body simulations have been measured extensively. The distribution of the total angular momentum of dark matter halos is also used…

Astrophysics · Physics 2017-08-23 Tom Abel , Rupert C. Croft , Lars Hernquist

We study merger histories of dark-matter haloes in a suite of N-body simulations that span different cosmological models. The simulated cases include the up-to-date WMAP5 cosmology and other test cases based on the Einstein-deSitter…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Eyal Neistein , Andrea V. Maccio' , Avishai Dekel

We investigate the effect of an assembly history on the evolution of dark matter (DM) halos of 10^{12} Msun/h using Constrained Realizations of random Gaussian fields. Five different realizations of a DM halo with distinct merging histories…

We introduce a novel dynamical model, named empirical triaxial orbit-superposition model, for the Milky Way halo. This model relies on minimal physical assumptions that the system is stationary, meaning the distribution function in 6D…

Astrophysics of Galaxies · Physics 2025-11-05 Ling Zhu , Xiang-Xiang Xue , Shude Mao , Chengqun Yang , Lan Zhang

Various analytic expressions have been proposed for the density profile of dark matter halos. We consider six of these expressions for which the density profile has a power-law fall-off rho proportional to r^{-3} at large radii and a…

Astrophysics · Physics 2007-05-23 Lawrence M. Widrow

Cosmological simulations indicate that cold dark matter (CDM) halos should be triaxial. Verifying observationally this theoretical prediction is, however, less than straightforward because the assembly of galaxies is expected to modify the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Stelios Kazantzidis , Mario G. Abadi , Julio F. Navarro

We conducted an analysis on dark matter halo properties following major and minor mergers to advance our understanding of halo evolution. In this work, we analyzed ~80,000 dark matter halos from the Bolshoi-Planck cosmological simulation…

Astrophysics of Galaxies · Physics 2017-11-28 Peter Wu , Shawn Zhang

We investigate the evolution of dark matter halo spin alignments with respect to cosmic filaments, exploring how halo mass, proximity to filaments, and major mergers influence their orientation over time. We perform a suite of dark…

Astrophysics of Galaxies · Physics 2026-04-01 David Tobar , Rory Smith , Antonio Montero-Dorta , Katarina Kraljic , Pablo López