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Accurate modelling of the one-to-two halo transition has long been difficult to achieve. We demonstrate that physically motivated halo definitions that respect the bimodal phase-space distribution of dark matter particles near halos…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-11 Edgar M. Salazar , Eduardo Rozo , Rafael García , Nickolas Kokron , Susmita Adhikari , Benedikt Diemer , Calvin Osinga

Collisionless dark matter galactic halos are expected to exhibit damped oscillations as a result of ongoing late time accretion. An n-body model of the cosmological assembly of a Milky Way-like halo is used to quantify the time dependence…

Astrophysics of Galaxies · Physics 2020-01-08 Raymond G. Carlberg

We measure the mass function of dark matter halos in a large set of collisionless cosmological simulations of flat LCDM cosmology and investigate its evolution at z<~2. Halos are identified as isolated density peaks, and their masses are…

Properties of dark matter halos are reviewed. Taken from different publications, we present results on (1) the mass and velocity functions, (2) density and velocity profiles, and (3) concentration of halos. In the range of radii…

Astrophysics · Physics 2007-05-23 Anatoly Klypin

In two previous papers (Salvador-Sol\'e 2012a,b), it was shown that: i) the typical structural and kinematic properties of haloes in (bottom-up) hierarchical cosmologies endowed with random Gaussian density perturbations of dissipationless…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-20 Eduard Salvador-Solé , Sinue Serra , Alberto Manrique

We present a new theory for the hierarchical clustering of dark matter (DM) halos based on stochastic differential equations, that constitutes a change of perspective with respect to existing frameworks (e.g., the excursion set approach);…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-18 Andrea Lapi , Luigi Danese

In the standard model of cosmic structure formation, dark matter haloes form by gravitational instability. The process is hierarchical: smaller systems collapse earlier, and later merge to form larger haloes. The galaxy clusters, hosted by…

Astrophysics · Physics 2009-11-13 Carlo Giocoli , Lidia Pieri , Giuseppe Tormen

We develop a flexible set of action-based distribution functions (DFs) for stellar haloes. The DFs have five free parameters, controlling the inner and outer density slope, break radius, flattening and anisotropy respectively. The DFs…

Astrophysics of Galaxies · Physics 2015-09-30 A. A. Williams , N. W. Evans

In excursion set theory the computation of the halo mass function is mapped into a first-passage time process in the presence of a barrier, which in the spherical collapse model is a constant and in the ellipsoidal collapse model is a fixed…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 Michele Maggiore , Antonio Riotto

Results from direct detection experiments are typically interpreted by employing an assumption about the dark matter velocity distribution, with results presented in the $m_\chi-\sigma_n$ plane. Recently methods which are independent of the…

High Energy Physics - Phenomenology · Physics 2015-10-14 Adam J. Anderson , Patrick J. Fox , Yonatan Kahn , Matthew McCullough

The non-linear, scale-dependent bias in the mass distribution of galaxies and the underlying dark matter is a key systematic affecting the extraction of cosmological parameters from galaxy clustering. Using 95 million halos from the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Elise Jennings , Carlton M. Baugh , Dylan Hatt

We use a set of large cosmological N-body simulations to study the internal structure of dark matter haloes which form in scale-free models. We find that the radius r_178 corresponding to a mean interior overdensity of 178 accurately…

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

The mass distribution of dark matter halos is a sensitive probe of primordial non-Gaussianity (NG). We derive an analytical formula of the halo mass function by perturbatively computing excursion set path-integrals for a non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-15 Ixandra Achitouv , Pier Stefano Corasaniti

It has been shown in previous work that DARKexp, which is a theoretically derived, maximum entropy, one shape parameter model for isotropic collisionless systems, provides very good fits to simulated and observed dark-matter halos.…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-20 Liliya L. R. Williams , Jens Hjorth , Radoslaw Wojtak

The universality of the halo mass function is investigated in the context of dark energy cosmologies. This widely used approximation assumes that the mass function can be expressed as a function of the matter density omega_m and the rms…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 J. Courtin , Y. Rasera , J. -M. Alimi , P. -S. Corasaniti , V. Boucher , A. Fuzfa

The baryon content of high-density regions in the universe is relevant to two critical unanswered questions: the workings of nurture effects on galaxies and the whereabouts of the missing baryons. In this paper, we analyze the distribution…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 A. Faltenbacher , A. Finoguenov , N. Drory

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

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 combine data from a number of N-body simulations to predict the abundance of dark halos in Cold Dark Matter universes over more than 4 orders of magnitude in mass. A comparison of different simulations suggests that the dominant…

This paper studies the scale and redshift variation of density and velocity distributions in self-gravitating collisionless dark matter flow by a halo-based non-projection approach. All particles are divided into halo and out-of-halo…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-28 Zhijie Xu