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The methods of determining the fractal dimension and irregularity scale in simulated galaxy catalogs and the application of these methods to the data of the 2dF and 6dF catalogs are analyzed. Correlation methods are shown to be correctly…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Nikita Yu. Lovyagin

The fractal properties of models of randomly placed $n$-dimensional spheres ($n$=1,2,3) are studied using standard techniques for calculating fractal dimensions in empirical data (the box counting and Minkowski-sausage techniques). Using…

Condensed Matter · Physics 2009-10-28 Daniel A. Hamburger , Ofer Biham , David Avnir

We present a systematic characterization of the fractal conduction pathways governing ionic transport in a non-crystalline solid below the glass-transition temperature. Using classical molecular dynamics simulations of lithium metasilicate,…

Soft Condensed Matter · Physics 2026-01-01 J. L. Iguain , F. O. Sanchez-Varreti , M. A. Frechero

The size distribution of ionized regions during the epoch of reionization -- a key ingredient in understanding the HI power spectrum observable by 21cm experiments -- can be modelled analytically using the excursion set formalism of random…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Aseem Paranjape , T. Roy Choudhury

Fractal dimensions have been used as a quantitative measure for structure of eigenstates of quantum many-body systems, useful for comparison to random matrix theory predictions or to distinguish many-body localized systems from chaotic…

Disordered Systems and Neural Networks · Physics 2025-01-30 Tuomas I. Vanhala , Niklas Järvelin , Teemu Ojanen

We analyze the volume-limited subsamples extracted from the sixteenth data release of the SDSS-IV eBOSS quasar survey spanning a redshift interval of $0.8 < z < 2.2$, to estimate the scale of transition to homogeneity in the Universe. The…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-16 Priya Goyal , Sunil Malik , Jaswant k. Yadav , T. R. Seshadri

Observations of neutral hydrogen in spiral galaxies reveal a sharp cutoff in the radial density profile at some distance from the center. Using 22 galaxies with known HI distributions as an example, we discuss the question of whether this…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 O. V. Abramova

We consider the degree to which "21 cm tomography" of the high-redshift Universe can distinguish different ionization histories. Using a new analytic model for the size distribution of HII regions that associates these ionized bubbles with…

Astrophysics · Physics 2009-09-29 Steven Furlanetto , Matias Zaldarriaga , Lars Hernquist

The measuring stations of a geophysical network are often spatially distributed in an inhomogeneous manner. The areal inhomogeneity can be well characterized by the fractal dimension D_H of the network, which is usually smaller than the…

Atmospheric and Oceanic Physics · Physics 2021-03-23 Valerio Capecchi , Alfonso Crisci , Samantha Melani , Marco Morabito , Paolo Politi

Surface scattering of neutral helium beams created by supersonic expansion is an established technique for measuring structural and dynamical properties of surfaces on the atomic scale. Helium beams have also been used in Fraunhofer and…

We explore the fractal nature of particle showers using Monte-Carlo simulation. We define the fractal dimension of showers measured in a high granularity calorimeter designed for a future lepton collider. The shower fractal dimension…

Instrumentation and Detectors · Physics 2015-06-18 Manqi Ruan , Daniel Jeans , Vincent Boudry , Jean-Claude Brient , Henri Videau

Evidence is presented that the galaxy distribution can be described as a fractal system in the redshift range of the FDF galaxy survey. The fractal dimension $D$ was derived using the FDF galaxy volume number densities in the spatially…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-22 G. Conde-Saavedra , A. Iribarrem , Marcelo B. Ribeiro

We detect the neutral hydrogen (HI) radial brightness temperature profile in large-scale haloes by stacking 48,430 galaxies selected from the 2dFGRS catalogue onto a set of 21-cm intensity maps obtained with the Parkes radio telescope,…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 Denis Tramonte , Yin-Zhe Ma

We present a study of the structure of the Galactic interstellar medium through the Delta-variance technique, related to the power spectrum and the fractal properties of infrared/sub-mm maps. Through this method, it is possible to provide…

Using data on the HI column density distribution in the local Universe, f(N_{HI}), we show how to determine g(N_{H}), the distribution of the total gas (HI+HII) column density. A simple power law fit to f(N_{HI}) fails due to bendings in…

Astrophysics · Physics 2009-11-07 Edvige Corbelli , Rino Bandiera

We study the fractal dimension of the contour of the liquid-gas interface in a spray. Our images include both, the linking region and the break-up region and are obtained with a high-resolution shadowgraph technique; this means that the…

Adaptation and Self-Organizing Systems · Physics 2007-05-23 R. Castrejon Garcia , A. Sarmiento Galan , J. R. Castrejon Pita , A. A. Castrejon Pita

The structures produced during the epoch of reionization by the action of radiation on neutral hydrogen are in principle different to those that arise through gravitational growth of initially small perturbations. We explore the difference…

Astrophysics · Physics 2009-11-13 Rupert A. C. Croft , Gabriel Altay

Modelling the distribution of neutral hydrogen (HI) in dark matter halos is important for studying galaxy evolution in the cosmological context. We use a novel approach to infer the HI-dark matter connection at the massive end ($m_{\rm HI}…

Astrophysics of Galaxies · Physics 2018-06-12 Niladri Paul , Tirthankar Roy Choudhury , Aseem Paranjape

Cohesive particles form agglomerates that are usually very porous. Their geometry, particularly their fractal dimension, depends on the agglomeration process (diffusion-limited or ballistic growth by adding single particles or…

Soft Condensed Matter · Physics 2023-12-07 Dietrich E. Wolf , Thorsten Pöschel

The Interstellar Medium seems to have an underlying fractal structure, which can be characterized through its fractal dimension (Df). However, several factors may affect the determination of Df, such as distortions due to projection, low…

Astrophysics · Physics 2008-03-11 Nestor Sanchez , Emilio J. Alfaro , Enrique Perez