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A new numerical technique to identify the cosmic web is proposed. It is based on locating multi-stream flows, i.e. the places where the velocity field is multi-valued. The method is local in Eulerian space, simple and computaionally…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Sergei F. Shandarin

We investigate the applicability of the moduli space approximation in theories with unbroken non-Abelian gauge symmetries. Such theories have massless magnetic monopoles that are manifested at the classical level as clouds of non-Abelian…

High Energy Physics - Theory · Physics 2009-11-07 Xingang Chen , Huidong Guo , Erick J. Weinberg

We present a Bayesian inference approach to estimating the cumulative mass profile and mean squared velocity profile of a globular cluster given the spatial and kinematic information of its stars. Mock globular clusters with a range of…

Astrophysics of Galaxies · Physics 2022-03-09 Gwendolyn M. Eadie , Jeremy J. Webb , Jeffrey S. Rosenthal

It is shown that the average magnitude - redshift diagram for a magnitude-limited sample of galaxies can be effectively used for mapping galaxy velocity field. This new approach is quantitatively introduced and applied to the CfA, ESO/LV…

Astrophysics · Physics 2016-06-08 Jacek Choloniewski

We present a simple model for the shape of the distribution function of galaxy peculiar velocities. We show how both nonlinear and linear theory terms combine to produce a distribution which has an approximately Gaussian core with…

Astrophysics · Physics 2009-10-31 Ravi K. Sheth , Antonaldo Diaferio

Using a set of 73 numerically simulated galaxy clusters, we have characterised the statistical and physical biases for three velocity dispersion and mass estimators, namely biweight, gapper and standard deviation, in the small number of…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-12 Antonio Ferragamo , José Alberto Rubiño-Martín , Juan Betancort-Rijo , Emiliano Munari , Barbara Sartoris , Rafael Barrena

The evolution of galaxy cluster counts is a powerful probe of several fundamental cosmological parameters. A number of recent studies using this probe have claimed tension with the cosmology preferred by the analysis of the Planck primary…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-21 C. E. Caldwell , I. G. McCarthy , I. K. Baldry , C. A. Collins , J. Schaye , S. Bird

Since the cosmic peculiar velocity field depends on small wave-number modes strongly, we cannot probe its universal properties unless we observe a sufficiently large region. We calculate the expected deviation (sample variance) of the…

Astrophysics · Physics 2009-10-30 Naoki Seto , Jun'ichi Yokoyama

What is the role of clusters of galaxies in probing the large-scale velocity field of the universe? We investigate the distribution of peculiar velocities of clusters of galaxies in the popular low-density ($\Omega=0.3$) flat…

Astrophysics · Physics 2009-10-22 Neta A. Bahcall , Renyue Cen , Mirt Gramann

We review the use of peculiar velocities of galaxies as a probe of cosmological models. We put particular emphasis on comparison of the peculiar velocity and density fields, focussing on the discrepancies between various recent analyses. We…

Astrophysics · Physics 2007-05-23 Michael A. Strauss , Michael Blanton

This paper examines several methods of tracing galaxies in N-body simulations and their effects on the derived galaxy statistics, especially measurements of velocity bias. Using two simulations with identical initial conditions, one…

Astrophysics · Physics 2009-06-16 F J Summers , Marc Davis , August E. Evrard

The velocity distribution of galaxies in clusters is not universal; rather, galaxies are segregated according to their spectral type and relative luminosity. We examine the velocity distributions of different populations of galaxies within…

Monte Carlo simulations are widely employed to measure the physical properties of glass-forming liquids in thermal equilibrium. Combined with local Monte Carlo moves, the Metropolis algorithm can also be used to simulate the relaxation…

Statistical Mechanics · Physics 2024-09-23 Ludovic Berthier , Federico Ghimenti Frédéric van Wijland

We employ a high-resolution dissipationless N-body simulation of a galaxy cluster to investigate the impact of subhalo selection on the resulting velocity distributions. Applying a lower limit on the present bound mass of subhalos leads to…

Astrophysics · Physics 2009-11-11 A. Faltenbacher , J. Diemand

We introduce a new phenomenological one-scale model for the evolution of domain wall networks, and test it against high-resolution field theory numerical simulations. We argue that previous numerical estimates of wall velocities are…

High Energy Physics - Phenomenology · Physics 2009-11-11 P. P. Avelino , C. J. A. P. Martins , J. C. R. E. Oliveira

Vision is one of the primary sensing modalities in autonomous driving. In this paper we look at the problem of estimating the velocity of road vehicles from a camera mounted on a moving car. Contrary to prior methods that train end-to-end…

Computer Vision and Pattern Recognition · Computer Science 2021-09-17 Robert McCraith , Lukas Neumann , Andrea Vedaldi

We use numerical simulations to study the relation between the velocity of the Local Group and its gravitational acceleration. This relation serves as a test for the kinematic origin of the CMB dipole and as a method for estimating beta. We…

Astrophysics · Physics 2007-05-23 P. Ciecielag , M. Chodorowski , A. Kudlicki

Autonomous vehicles (AVs) allow new ways of regulating the traffic flow on road networks. Most of available results in this direction are based on microscopic approaches, where ODEs describe the evolution of regular cars and AVs. In this…

Analysis of PDEs · Mathematics 2020-04-21 Mauro Garavello , Paola Goatin , Thibault Liard , Benedetto Piccoli

We measure the distribution of velocity dispersions of groups of galaxies identified in the UZC catalog; we use the distribution to derive the group mass function. We introduce a new method which makes efficient use of the entire magnitude…

Astrophysics · Physics 2009-11-10 Armando Pisani , Massimo Ramella , Margaret J. Geller

Galaxy distances and derived radial peculiar velocity catalogs constitute valuable datasets to study the dynamics of the Local Universe. However, such catalogs suffer from biases whose effects increase with the distance. Malmquist biases…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Jenny G. Sorce