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We evaluate the accuracy of semi-analytic merger-trees by comparing them with the merging histories of dark-matter halos in N-body simulations, focusing on the joint distribution of the number of progenitors and their masses. We first…

Astrophysics · Physics 2009-10-30 Rachel S. Somerville , Gerard Lemson , Tsafrir S. Kolatt , Avishai Dekel

The internal structure and abundance of dark matter halos and subhalos are powerful probes of the nature of dark matter. In order to compare observations with dark matter models, accurate theoretical predictions of these quantities are…

In the present work, we extend the classic halo model for the large-scale matter distribution including a triaxial model for the halo profiles and their alignments. In particular, we derive general expressions for the halo-matter cross…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-21 M. A. Sgró , D. J. Paz , M. E. Merchán

We follow the spin vector evolutions of well resolved dark matter haloes (containing more than 300 particles) in merger tree main branches from the Millennium and Millennium-II N-body simulations, from z about 3.3 to z = 0. We find that…

Astrophysics of Galaxies · Physics 2025-05-06 Jun Hou , Zhijian Luo , Cedric G. Lacey

We review the formalism and applications of the halo-based description of nonlinear gravitational clustering. In this approach, all mass is associated with virialized dark matter halos; models of the number and spatial distribution of the…

Astrophysics · Physics 2011-07-19 Asantha Cooray , Ravi Sheth

This paper uses numerical simulations to test the formation time distribution of dark matter haloes predicted by the analytic excursion set approaches. The formation time distribution is closely linked to the conditional mass function and…

Astrophysics · Physics 2009-11-10 W. P. Lin , Y. P. Jing , Lihwai Lin

(Abridged) We develop the halo model of large-scale structure to include triaxial dark matter haloes and their intrinsic alignments. As a direct application we derive general expressions for the power spectrum. This we calculate for two…

Astrophysics · Physics 2009-11-10 R. E. Smith , P. I. R. Watts

Merger trees track the evolution of halos across multiple snapshots. They assign for halos of a particular snapshot, the set of halos from previous snapshots they possibly originated from. In this work, Association rule analysis a well…

Instrumentation and Methods for Astrophysics · Physics 2017-01-18 B. Hareesh Gautham , Rahul Nigam

Shape estimates that quantify the halo anisotropic mass distribution are valuable parameters that provide information on their assembly process and evolution. Measurements of the mean shapes for a sample of cluster-sized halos can be used…

In the hierarchical structure formation model cosmic halos are supposed to form by accretion of smaller units along anisotropic direction, defined by large-scale filamentary structures. After the epoch of primary mass aggregation (which…

Astrophysics · Physics 2015-06-24 Manolis Plionis , Cinthia Ragone , Spyros Basilakos

Various laboratory-based experiments are underway attempting to detect dark matter directly. The event rates and detailed signals expected in these experiments depend on the dark matter phase space distribution on sub-milliparsec scales.…

Astrophysics · Physics 2011-08-31 Daniele S. M. Fantin , Michael R. Merrifield , Anne M. Green

We revisit the non-sphericity of cluster-mass scale halos from cosmological N-body simulation on the basis of triaxial modelling. In order to understand the difference between the simulation results and the conventional ellipsoidal collapse…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-12 Daichi Suto , Tetsu Kitayama , Takahiro Nishimichi , Shin Sasaki , Yasushi Suto

The merging history of dark matter halos is computed with the Merging Cell Model proposed by Rodrigues & Thomas (1996). While originally discussed in the case of scale-free power spectra, it is developed and tested here in the framework of…

Astrophysics · Physics 2009-10-31 Barbara Lanzoni , Gary A. Mamon , Bruno Guiderdoni

We present a model for the dynamical evolution of subhaloes based on an approach combining numerical and analytical methods. Our method is based on tracking subhaloes in an N-body simulation up to the last point that it can be resolved, and…

Astrophysics of Galaxies · Physics 2017-09-20 Vimal Simha , Shaun Cole

In this work, we aim at investigating the morphology evolution of Milky Way mass-like dark matter haloes selected from the CIELO and IllustrisTNG Projects. The connection between halo shapes and their environment has been studied in…

Statistics of lensed arcs in clusters of galaxies serve as a powerful probe of both the non-sphericity and the inner slope of dark matter halos. We develop a semi-analytic method to compute the number of arcs in triaxial dark matter halos.…

Astrophysics · Physics 2009-11-07 Masamune Oguri , Jounghun Lee , Yasushi Suto

We combine the physics of the ellipsoidal collapse model with the excursion set theory to study the shapes of dark matter halos. In particular, we develop an analytic approximation to the nonlinear evolution that is more accurate than the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Graziano Rossi , Ravi K. Sheth , Giuseppe Tormen

We present a technique for constructing equilibrium triaxial N-body haloes with nearly arbitrary density profiles, axial ratios and spin parameters. The method is based on the way in which structures form in hierarchical cosmological…

Astrophysics · Physics 2009-11-10 Ben Moore , Stelios Kazantzidis , Juerg Diemand , Joachim Stadel

In hierarchical models, the time derivative of the halo mass function may be thought of as the difference of two terms - a creation term, which describes the increase in the number of haloes of mass m from mergers of less massive objects,…

Astrophysics · Physics 2009-07-10 Jorge Moreno , Carlo Giocoli , Ravi K. Sheth

We analyse the impact of galaxy--halo misalignment on the ability of weak lensing studies to constrain the shape of dark matter haloes, using a combination of the Millennium dark matter N-body simulation and different semi-analytic galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-07 Philip E. Bett