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N-body simulations are the most powerful method to study the non-linear evolution of large-scale structure. However, they require large amounts of computational resources, making unfeasible their direct adoption in scenarios that require…

宇宙学与河外天体物理 · 物理学 2023-04-14 Miguel Conceição , Alberto Krone-Martins , Antonio da Silva , Ángeles Moliné

We study the formation of dark matter halos in the concordance LCDM model over a wide range of redshifts, from z=20 to the present. Our primary focus is the halo mass function, a key probe of cosmology. By performing a large suite of…

天体物理学 · 物理学 2008-11-26 Zarija Lukic , Katrin Heitmann , Salman Habib , Sergei Bashinsky , Paul M. Ricker

The abundance of dark matter haloes is one of the key probes of the growth of structure and expansion history of the Universe. Theoretical predictions for this quantity usually assume that, when expressed in a certain form, it depends only…

宇宙学与河外天体物理 · 物理学 2021-12-22 Lurdes Ondaro-Mallea , Raul E. Angulo , Matteo Zennaro , Sergio Contreras , Giovanni Aricò

Dark matter (DM) halos form hierarchically in the Universe through a series of merger events. Cosmological simulations can represent this series of mergers as a graph-like ``tree'' structure. Previous work has shown these merger trees are…

We perform N-body simulations for $f(T)$ gravity using the ME-Gadget code, in order to investigate for the first time the structure formation process in detail. Focusing on the power-law model, and considering the model-parameter to be…

宇宙学与河外天体物理 · 物理学 2022-10-12 Yiqi Huang , Jiajun Zhang , Xin Ren , Emmanuel N. Saridakis , Yi-Fu Cai

We demonstrate the potential of Deep Learning methods for measurements of cosmological parameters from density fields, focusing on the extraction of non-Gaussian information. We consider weak lensing mass maps as our dataset. We aim for our…

宇宙学与河外天体物理 · 物理学 2017-07-19 Jorit Schmelzle , Aurelien Lucchi , Tomasz Kacprzak , Adam Amara , Raphael Sgier , Alexandre Réfrégier , Thomas Hofmann

Cold dark matter (CDM) is a well established paradigm to describe cosmological structure formation, and works extraordinarily well on large, linear, scales. Progressing further in dark matter physics requires being able to understand…

宇宙学与河外天体物理 · 物理学 2016-05-20 David J. E. Marsh

Testing the standard cosmological model ($\Lambda$CDM) at small scales is challenging. Galaxies that inhabit low-mass dark matter halos provide an ideal test bed for dark matter models by linking observational properties of galaxies at…

星系天体物理 · 物理学 2023-06-14 Amy Sardone , Annika H. G. Peter , Alyson M. Brooks , Jane Kaczmarek

We explore the impact of a LWDM cosmological scenario on the clustering properties of large-scale structure in the Universe. We do this by extending the halo model. The new development is that we consider two components to the mass density:…

宇宙学与河外天体物理 · 物理学 2013-05-29 Robert E. Smith , Katarina Markovic

For many analyses in cosmology it is necessary to reconstruct the likely distribution of unobserved fields, such as dark matter or non-luminous baryons, from observed luminous tracers. The dominant approach in cosmology has been to use the…

宇宙学与河外天体物理 · 物理学 2025-12-16 Jordan Krywonos , Yurii Kvasiuk , Matthew C. Johnson , Moritz Münchmeyer

We use a high resolution $\Lambda$CDM numerical simulation to calculate the mass function of dark matter haloes down to the scale of dwarf galaxies, back to a redshift of fifteen, in a 50 $h^{-1}$Mpc volume containing 80 million particles.…

天体物理学 · 物理学 2008-11-26 Darren Reed , Jeffrey Gardner , Thomas Quinn , Joachim Stadel , Mark Fardal , George Lake , Fabio Governato

The mass distribution of halos, as specified by the halo mass function, is a key input for several cosmological probes. The sizes of $N$-body simulations are now such that, for the most part, results need no longer be statistics-limited,…

宇宙学与河外天体物理 · 物理学 2015-05-19 Suman Bhattacharya , Katrin Heitmann , Martin White , Zarija Lukić , Christian Wagner , Salman Habib

Using cosmological N-body simulations we study the line-of-sight velocity distribution of dark matter haloes focusing on the lowest-order even moments, dispersion and kurtosis, and their application to estimate the mass profiles of…

天体物理学 · 物理学 2009-11-13 Radoslaw Wojtak , Ewa L. Lokas , Stefan Gottloeber , Gary A. Mamon

The dark matter halo mass function (HMF) is a characteristic property of cosmological structure formation models, quantifying the number density of dark matter haloes per unit mass in the Universe. A key goal of current and planned large…

宇宙学与河外天体物理 · 物理学 2013-07-01 Steven Murray , Chris Power , Aaron Robotham

We evaluate the ability of Convolutional Neural Networks (CNNs) to predict galaxy cluster masses in the BAHAMAS hydrodynamical simulations. We train four separate single-channel networks using: stellar mass, soft X-ray flux, bolometric…

宇宙学与河外天体物理 · 物理学 2020-10-07 Z. Yan , A. J. Mead , L. Van Waerbeke , G. Hinshaw , I. G. McCarthy

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…

天体物理学 · 物理学 2009-09-25 A. Jenkins , C. S. Frenk , S. D. M. White , J. M. Colberg , S. Cole , A. E. Evrard , H. M. P. Couchman , N. Yoshida

We present a method to numerically estimate the densities of a discretely sampled data based on binary space partitioning tree. We start with a root node containing all the particles and then recursively divide each node into two nodes each…

天体物理学 · 物理学 2015-06-24 Sanjib Sharma , Matthias Steinmetz

We present a detailed numerical study of the impact that cosmological models featuring a direct interaction between the Dark Energy component that drives the accelerated expansion of the Universe and Cold Dark Matter can have on the linear…

宇宙学与河外天体物理 · 物理学 2015-05-20 Marco Baldi

We present a deep machine learning (ML)-based technique for accurately determining $\sigma_8$ and $\Omega_m$ from mock 3D galaxy surveys. The mock surveys are built from the AbacusCosmos suite of $N$-body simulations, which comprises 40…

宇宙学与河外天体物理 · 物理学 2020-02-12 Michelle Ntampaka , Daniel J. Eisenstein , Sihan Yuan , Lehman H. Garrison

By means of N-body simulations, we study early structure formation in the presence of a scaling distribution of cosmic string loops. Cosmic string loops dominate the high redshift halo mass function while the fluctuations seeded by the…

宇宙学与河外天体物理 · 物理学 2024-02-12 Hao Jiao , Robert Brandenberger , Alexandre Refregier