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The density of dark matter near the Sun is important for experiments hunting for dark matter particles in the laboratory, and for constraining the local shape of the Milky Way's dark matter halo. Estimates to date have typically assumed…

Astrophysics of Galaxies · Physics 2022-02-16 S. Sivertsson , J. I. Read , H. Silverwood , P. F. de Salas , K. Malhan , A. Widmark , C. F. P. Laporte , S. Garbari , K. Freese

The density profile of simulated dark matter structures is fairly well-established, and several explanations for its characteristics have been put forward. In contrast, the radial variation of the velocity anisotropy has still not been…

Astrophysics · Physics 2014-11-18 Steen H. Hansen

This paper presents two families of phase-space distribution functions (DFs) that generate scale-free spheroidal mass densities in scale-free spherical potentials. The `case I' DFs are anisotropic generalizations of the flattened f(E,L_z)…

Astrophysics · Physics 2015-06-24 Jos H. J. de Bruijne , Roeland P. van der Marel , P. Tim de Zeeuw

We present mass models for the dark matter component of seven dwarf galaxies taken from "The HI Nearby Galaxy Survey" (THINGS) and compare these with those from numerical Lambda Cold Dark Matter (LCDM) simulations. The THINGS…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Se-Heon Oh , W. J. G. de Blok , Elias Brinks , Fabian Walter , Robert C. Kennicutt

We present a field-based approach to the analysis of cosmic shear data to infer jointly cosmological parameters and the dark matter distribution. This forward modelling approach samples the cosmological parameters and the initial matter…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-17 Natalia Porqueres , Alan Heavens , Daniel Mortlock , Guilhem Lavaux

We present a simulation-based inference framework using a convolutional neural network to infer dynamical masses of galaxy clusters from their observed 3D projected phase-space distribution, which consists of the projected galaxy positions…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-18 Doogesh Kodi Ramanah , Radosław Wojtak , Nikki Arendse

Generative Adversarial Networks (GANs) have shown immense potential in fields such as text and image generation. Only very recently attempts to exploit GANs to statistical-mechanics models have been reported. Here we quantitatively test…

Statistical Mechanics · Physics 2024-05-07 Daniele Lanzoni , Olivier Pierre-Louis , Francesco Montalenti

Weak gravitational lensing is considered to be one of the most powerful tools to study the mass and the mass distribution of galaxy clusters. However, the mass-sheet degeneracy transformation has limited its success. We present a novel…

Astrophysics · Physics 2007-05-23 M. Bradac , P. Schneider , M. Lombardi , T. Erben

We present the analysis of a sample of twenty-four SLACS-like galaxy-galaxy strong gravitational lens systems with a background source and deflectors from the Illustris-1 simulation. We study the degeneracy between the complex mass…

Astrophysics of Galaxies · Physics 2020-05-27 W. Enzi , S. Vegetti , G. Despali , J. -W. Hsueh , R. B. Metcalf

We examine the problem tidally-induced mass loss from collisionless systems such as dark matter haloes. We develop a model for tidal mass loss, based upon the phase space distribution of particles, which accounts for how both tidal and…

Astrophysics · Physics 2008-11-26 M. Kampakoglou , A. J. Benson

The nonlinearity of dynamics in systems biology makes it hard to infer them from experimental data. Simple linear models are computationally efficient, but cannot incorporate these important nonlinearities. An adaptive method based on the…

Quantitative Methods · Quantitative Biology 2015-08-19 Bryan C. Daniels , Ilya Nemenman

The matter distribution of the Universe can be mapped through the weak gravitational lensing (WL) effect: small distortions of the shapes of distant galaxies, which reflects the inhomogeneity of the cosmic density field. The most dominant…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-21 Shohei D. Aoyama , Ken Osato , Masato Shirasaki

We derive the local dark matter density by applying the integrated Jeans equation method from Silverwood et al. (2016) to SDSS-SEGUE G-dwarf data processed and presented by B\"udenbender et al. (2015). We use the MultiNest Bayesian nested…

Astrophysics of Galaxies · Physics 2018-05-02 Sofia Sivertsson , Hamish Silverwood , Justin I. Read , Gianfranco Bertone , Pascal Steger

Systems of self-gravitating fermions constitute a topic of great interest in astrophysics, due to the wide field of applications. In this paper, we consider the gravitational equilibrium of spherically symmetric Newtonian models of…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-01 Marco Merafina , Giuseppe Alberti

We present a numerical method for learning the dynamics of slow components of unknown multiscale stochastic dynamical systems. While the governing equations of the systems are unknown, bursts of observation data of the slow variables are…

Machine Learning · Computer Science 2024-08-28 Yuan Chen , Dongbin Xiu

We add to the lore of spherical, stellar-system models a two-parameter family with an anisotropic velocity dispersion, and a central point mass (``black hole''). The ratio of the tangential to radial dispersions, is constant--and…

Astrophysics · Physics 2009-10-28 Mordehai Milgrom

N-body simulations are essential for understanding the formation and evolution of structure in the Universe. However, the discrete nature of these simulations affects their accuracy when modelling collisionless systems. We introduce a new…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Oliver Hahn , Raul E. Angulo

We present the theoretical framework to efficiently solve the Jeans equations for multi-component axisymmetric stellar systems, focusing on the scaling of all quantities entering them. The models may include an arbitrary number of stellar…

Astrophysics of Galaxies · Physics 2021-06-30 C. Caravita , L. Ciotti , S. Pellegrini

(Abridged) We present mass models of a sample of 14 spiral and 14 S0 galaxies that constrain their stellar and dark matter content. For each galaxy we derive the stellar mass distribution from near-infrared photometry under the assumptions…

Astrophysics of Galaxies · Physics 2011-04-07 Michael J. Williams , Martin Bureau , Michele Cappellari

We present a simple and accurate method to constrain galaxy bias based on the distribution of counts in cells. The most unique feature of our technique is that it is applicable to non-linear scales, where both dark matter statistics and the…

Astrophysics · Physics 2009-11-10 Istvan Szapudi , Jun Pan