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The Voids-within-Voids-within-Voids (VVV) project used dark-matter-only simulations to study the abundance and structure of dark matter haloes over the full mass range populated in the standard $\Lambda\mathrm{CDM}$ cosmology. Here we…

We present a new cosmological probe for galaxy clusters, the halo sparsity. This characterises halos in terms of the ratio of halo masses measured at two different radii and carries cosmological information encoded in the halo mass profile.…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-08 P. S. Corasaniti , S. Ettori , Y. Rasera , M. Sereno , S. Amodeo , M. -A. Breton , V. Ghirardini , D. Eckert

The clustering of galaxies in ongoing and upcoming galaxy surveys contains a wealth of cosmological information, but extracting this information is a non-trivial task since galaxies and their host haloes are stochastic tracers of the matter…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 Tobias Baldauf , Uroš Seljak , Robert E. Smith , Nico Hamaus , Vincent Desjacques

We use bootstrapping to estimate the bias of concentration estimates on N-body dark matter halos as a function of particle number. We find that algorithms based on the maximum radial velocity and radial particle binning tend to overestimate…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-14 C. N. Poveda-Ruiz , J. E. Forero-Romero , J. C. Muñoz-Cuartas

Bayesian Optimization (BO) is a common solution to search optimal hyperparameters based on sample observations of a machine learning model. Existing BO algorithms could converge slowly even collapse when the potential observation noise…

Computer Vision and Pattern Recognition · Computer Science 2022-10-10 Lei Cui , Yangguang Li , Xin Lu , Dong An , Fenggang Liu

An alternative bosonic dark matter model is examined in detail via high-resolution simulations. These bosons have particle mass of order $10^{-22}eV$ and are non-interacting. If they do exist and can account for structure formation, these…

Astrophysics · Physics 2010-01-15 Tak-Pong Woo , Tzihong Chiueh

A new multi-dimensional Hierarchical Structure Finder (HSF) to study the phase-space structure of dark matter in N-body cosmological simulations is presented. The algorithm depends mainly on two parameters, which control the level of…

Astrophysics · Physics 2015-05-13 M. Maciejewski , S. Colombi , V. Springel , C. Alard , F. R. Bouchet

The dark matter halo sparsity, i.e. the ratio between spherical halo masses enclosing two different overdensities, provides a non-parametric proxy of the halo mass distribution which has been shown to be a sensitive probe of the…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-30 P. S. Corasaniti , A. M. C. Le Brun , T. R. G. Richardson , Y. Rasera , S. Ettori , M. Arnaud , G. W Pratt

We present a proof-of-concept of a novel and fully Bayesian methodology designed to detect halos of different masses in cosmological observations subject to noise and systematic uncertainties. Our methodology combines the previously…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-08 Alexander I. Merson , Jens Jasche , Filipe B. Abdalla , Ofer Lahav , Benjamin Wandelt , D. Heath Jones , Matthew Colless

We consider the problem of identification of safe regions in the environment of an autonomous system. The environment is divided into a finite collections of Voronoi cells, with each cell having a representative, the Voronoi center. The…

Systems and Control · Electrical Eng. & Systems 2024-12-17 Aneesh Raghavan , Karl H Johansson

We calculate the non-linear virialization density, $\Delta_c$, of halos under spherical collapse from peaks with an arbitrary initial and final density profile. This is in contrast to the standard calculation of $\Delta_c$ which assumes…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Douglas Rubin , Abraham Loeb

A noise-based non-parametric technique for detecting nebulous objects, for example, irregular or clumpy galaxies, and their structure in noise is introduced. "Noise-based" and "non-parametric" imply that this technique imposes negligible…

Instrumentation and Methods for Astrophysics · Physics 2015-09-08 Mohammad Akhlaghi , Takashi Ichikawa

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

In recent work (Seljak, Hamaus and Desjacques 2009) it was found that weighting central halo galaxies by halo mass can significantly suppress their stochasticity relative to the dark matter, well below the Poisson model expectation. In this…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Nico Hamaus , Uros Seljak , Vincent Desjacques , Robert E. Smith , Tobias Baldauf

The density profiles of dark matter halos are typically modeled using empirical formulae fitted to the density profiles of relaxed halo populations. We present a neural network model that is trained to learn the mapping from the raw density…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-08 Luisa Lucie-Smith , Hiranya V. Peiris , Andrew Pontzen , Brian Nord , Jeyan Thiyagalingam , Davide Piras

We present estimates of the nonlinear bias of cosmological halo formation, spanning a wide range in the halo mass from $\sim 10^{5} M_\odot$ to $\sim 10^{12} M_\odot$, based upon both a suite of high-resolution cosmological N-body…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Kyungjin Ahn , Ilian T. Iliev , Paul R. Shapiro , ChaiChalit Srisawat

We present a Bayesian reconstruction algorithm to generate unbiased samples of the underlying dark matter field from halo catalogues. Our new contribution consists of implementing a non-Poisson likelihood including a deterministic…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Metin Ata , Francisco-Shu Kitaura , Volker Müller

We estimate the two-point correlation function of dark matter haloes, with masses >10^{13} h^{-1} Mo, that have or not significant substructure. The haloes are identified with a friends of friends algorithm in a large LCDM simulation at two…

Astrophysics · Physics 2009-11-13 N. Espino-Briones , M. Plionis , C. Ragone-Figueroa

Halo-independent methods for analyzing direct detection experiments can provide robust results while making no assumptions about the dark matter halo in our galaxy. We extend existing methods to the case of unbinned data, which is…

High Energy Physics - Phenomenology · Physics 2014-11-18 Yonatan Kahn

We present a new approach for modelling galaxy/halo bias that utilizes the full non-linear information contained in the moments of the matter density field, which we derive using a set of numerical simulations. Although our method is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Jennifer E. Pollack , Robert E. Smith , Cristiano Porciani