English
Related papers

Related papers: ZOBOV: a parameter-free void-finding algorithm

200 papers

Void number counts (VNC) indicates the number of low-density regions in the large-scale structure (LSS) of the Universe, and we propose to use it as an effective cosmological probe. By generating the galaxy mock catalog based on Jiutian…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-06 Yingxiao Song , Qi Xiong , Yan Gong , Furen Deng , Kwan Chuen Chan , Xuelei Chen , Qi Guo , Yun Liu , Wenxiang Pei

We identify cosmic voids from galaxy density fields under the theory of void-cluster correspondence. We extend the previous novel void-identification method developed for the matter density field to the galaxy density field for practical…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-26 Junsup Shim , Changbom Park , Juhan Kim , Sungwook E. Hong

Voronoi tessellations are used to partition the Euclidean space into polyhedral regions, which are called Voronoi cells. Labeling the Voronoi cells with the class information, we can map any classification problem into a Voronoi…

Machine Learning · Computer Science 2021-06-17 Rahman Salim Zengin , Volkan Sezer

We present a new algorithm for finding isolated zeros of a system of real-valued functions in a bounded interval in $\mathbb{R}^n$. It uses the Chebyshev proxy method combined with a mixture of subdivision, reduction methods, and…

High energy experimental data can be viewed as a sampling of the relevant phase space. We point out that one can apply Voronoi tessellations in order to understand the underlying probability distributions in this phase space. Interesting…

High Energy Physics - Phenomenology · Physics 2015-11-10 Dipsikha Debnath , James S. Gainer , Doojin Kim , Konstantin T. Matchev

Unsupervised classification called clustering is a process of organizing objects into groups whose members are similar in some way. Clustering of uncertain data objects is a challenge in spatial data bases. In this paper we use Probability…

Databases · Computer Science 2013-12-10 Ramachandra Rao Kurada

(Abridged) We investigate the power of void statistics to constrain galaxy bias and the amplitude of dark matter fluctuations. We use the halo occupation distribution (HOD) framework to describe the relation between galaxies and dark…

Astrophysics · Physics 2011-02-11 Jeremy L. Tinker , David H. Weinberg , Michael S. Warren

The dark soliton solution of the Gross-Pitaevskii equation in one dimension has two parameters that do not change the energy of the solution: the global phase of the condensate wave function and the position of the soliton. These…

Mesoscale and Nanoscale Physics · Physics 2024-01-19 Jacek Dziarmaga

Under the assumption of a void-filled Universe we investigate if the characteristic scale of voids can be determined from existing surveys. We use the Voronoi tessellation to create mock surveys and study the properties of the first…

Astrophysics · Physics 2015-06-24 Dalia S. Goldwirth , Luiz Nicolaci da Costa , Rien Van de Weygaert

We present a new void search algorithm for automated detection of voids in three-dimensional redshift surveys. Based on a model in which the main features of the LSS of the Universe are voids and walls, we classify the galaxies into wall…

Astrophysics · Physics 2009-10-28 Hagai El-Ad , Tsvi Piran , Luiz Nicolaci da Costa

We consider escaping saddle points of nonconvex problems where only the function evaluations can be accessed. Although a variety of works have been proposed, the majority of them require either second or first-order information, and only a…

Optimization and Control · Mathematics 2022-10-05 Hualin Zhang , Huan Xiong , Bin Gu

This paper investigates zeroth-order (ZO) finite-sum composite optimization. Recently, variance reduction techniques have been applied to ZO methods to mitigate the non-vanishing variance of 2-point estimators in constrained/composite…

Optimization and Control · Mathematics 2026-01-09 Silan Zhang , Yujie Tang

Using numerical simulations, we investigate the large-scale gravitational clustering in a flat universe dominated by cold plus hot dark matter (i.e., $\Omega_0=\ocdm+\ohdm+\obaryon=1$). Primordial density fluctuation spectrum is taken to…

Astrophysics · Physics 2010-12-09 Y. P. Jing , H. J. Mo , G. Boerner , L. Z. Fang

Cosmic voids are a promising environment to characterize neutrino-induced effects on the large-scale distribution of matter in the universe. We perform a comprehensive numerical study of the statistical properties of voids, identified both…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Elena Massara , Francisco Villaescusa-Navarro , Matteo Viel , P. M. Sutter

Clustering large spatial databases is an important problem, which tries to find the densely populated regions in a spatial area to be used in data mining, knowledge discovery, or efficient information retrieval. However most algorithms have…

Databases · Computer Science 2009-09-25 Mohamed A. El-Zawawy , Mohamed E. El-Sharkawi

We measure the void probability function (VPF) of galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS). The VPF provides complementary information to standard two-point statistics in that it is sensitive to galaxy bias in the most…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-20 Kilian Walsh , Jeremy Tinker

We explore voids in dark matter and halo fields from simulations of $\Lambda$CDM and Hu-Sawicki $f(R)$ models. In $f(R)$ gravity, dark matter void abundances are greater than that of general relativity (GR). However, when using haloes to…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-06 Yan-Chuan Cai , Nelson Padilla , Baojiu Li

We consider optimization problems that arise when estimating a set of unknown parameters from experimental data, particularly in the context of nuclear density functional theory. We examine the cost of not having derivatives of these…

Computational Physics · Physics 2015-02-06 Stefan M. Wild , Jason Sarich , Nicolas Schunck

We present an algorithm which is designed to allow the efficient identification and preliminary dynamical analysis of thousands of structures and substructures in large N-body simulations. First we utilise a refined density gradient system…

Astrophysics · Physics 2009-11-10 Jochen Weller , Jeremiah P Ostriker , Paul Bode , Laurie Shaw

We propose a densification algorithm to improve the Line Of Variations (LOV) method for impact monitoring, which can fail when the information is too little, as it may happen in difficult cases. The LOV method uses a 1-dimensional sampling…

Instrumentation and Methods for Astrophysics · Physics 2020-07-07 A. Del Vigna , F. Guerra , G. B. Valsecchi