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Based on the drift-kinetic theory, we develop a model for particle acceleration and transport in solar flares. The model describes the evolution of the particle distribution function by means of a numerical simulation of the drift-kinetic…

Solar and Stellar Astrophysics · Physics 2015-05-18 T. Minoshima , S. Masuda , Y. Miyoshi

Previously, we showed that surface density profiles of the form of a power-law times a Sersic function satisfy the hydrostatic Jeans equations, a variety of observational constraints, and the condition of a minimal radial entropy profile in…

Astrophysics of Galaxies · Physics 2019-09-27 Curtis Struck , Bruce G. Elmegreen

The Milky Way's satellite galaxies and Globular Clusters (GCs) are known to exhibit an anisotropic spatial distribution. We examine in detail this anisotropy by the means of the inertia tensor. We estimate the statistical significance of…

Astrophysics of Galaxies · Physics 2018-08-29 N. R. Arakelyan , S. V. Pilipenko , N. I. Libeskind

In this paper we study the equilibrium configurations of anisotropic self-gravitating fermions, by extending to general relativity the solutions obtained in a previous paper. This treatment also generalizes to anisotropic systems the…

Astrophysics of Galaxies · Physics 2015-07-23 Marco Merafina , Giuseppe Alberti

Distinguishing a core and a cusp within dark matter halos is complexified by the existence of mass-anisotropy degeneracy, where various combinations of velocity anisotropy ($\beta$) and inner density slope ($\gamma$) yield similar…

Astrophysics of Galaxies · Physics 2025-02-21 Dafa Wardana , Masashi Chiba , Kohei Hayashi

The galactic component in clusters is commonly thought to be generally nonrotating and in a dynamical state different from that of a collisionally relaxed system. In practice, a test of such a picture is often not available. We consider the…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-11 Giovanni Ferrami , Giuseppe Bertin , Claudio Grillo , Amata Mercurio , Piero Rosati

This paper shows how a self-consistent dynamical model can be obtained by fitting the gravitational potential of the Milky Way to the stellar kinematics and densities from Gaia data. Using the Besancon Galaxy Model we derive a potential and…

In order to address the question of whether spiral disturbances in galaxy discs are gravitationally coupled to the halo, we conduct simulations of idealized models of disc galaxies. We compare growth rates of spiral instabilities in…

Astrophysics of Galaxies · Physics 2021-07-14 J. A. Sellwood

Galactic scaling relations between the (surface densities of) the gas mass and the star formation (SF) rate are known to develop substantial scatter or even change form when considered below a certain spatial scale. We quantify how this…

Astrophysics of Galaxies · Physics 2015-06-18 J. M. Diederik Kruijssen , Steven N. Longmore

We study galaxy evolution and spatial patterns in the surroundings of a sample of 2dF groups. Our aim is to find evidence of galaxy evolution and clustering out to 10 times the virial radius of the groups and so redefine their properties…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 A. L. B. Ribeiro , M. Trevisan , P. A. A. Lopes , A. C. Schilling

This review is a kinetic theory study investigating the effects of inelasticity on the structure of the non-equilibrium states, in particular on the behavior of the velocity distribution in the high energy tails. Starting point is the…

Statistical Mechanics · Physics 2007-05-23 R. Brito , M. H. Ernst

We continue the study of collisionless systems governed by additive $r^{-\alpha}$ interparticle forces by focusing on the influence of the force exponent $\alpha$ on radial orbital anisotropy. In this preparatory work we construct the…

Astrophysics of Galaxies · Physics 2015-07-22 Pierfrancesco Di Cintio , Luca Ciotti , Carlo Nipoti

I show that gravitational scattering of dark-matter objects of 10^4 solar masses and speeds of 10 km/s, provides the cross-section per unit mass required in self-interacting dark matter models that alleviate the small-scale structure…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-27 Abraham Loeb

The existence of dwarf spheroidal galaxies with high internal velocity dispersions orbiting in the Milky Way raises questions about their dark matter content and lifetime. In this paper, we present an alternative solution to the dark matter…

Astrophysics · Physics 2014-10-13 M. A. Gomez-Flechoso , R. Fux , L. Martinet

A chemodynamical model of our galaxy is fitted to data from DR17 of the APOGEE survey supplemented with data from the StarHorse catalogue and gaia DR3. Dynamically, the model is defined by action-based distribution functions for dark matter…

Astrophysics of Galaxies · Physics 2023-10-30 James Binney , Eugene Vasiliev

We study the impact of the dark matter velocity distribution modelling on signals from velocity-dependent dark matter annihilation in Milky Way dwarf spheroidal galaxies. Using the high resolution APOSTLE simulations, we identify analogues…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-15 Keagan Blanchette , Erin Piccirillo , Nassim Bozorgnia , Louis E. Strigari , Azadeh Fattahi , Carlos S. Frenk , Julio F. Navarro , Till Sawala

We use high-resolution N-body simulations to follow the formation and evolution of tidal streams associated to dwarf spheroidal galaxies (dSphs). The dSph models are embedded in dark matter (DM) haloes with either a centrally-divergent…

Astrophysics of Galaxies · Physics 2016-02-22 Raphaël Errani , Jorge Peñarrubia , Giuseppe Tormen

The distribution of partition function zeros is studied for the $\pm J$ model of spin glasses on the Bethe lattice. We find a relation between the distribution of complex cavity fields and the density of zeros, which enables us to obtain…

Disordered Systems and Neural Networks · Physics 2010-06-16 Yoshiki Matsuda , Markus Mueller , Hidetoshi Nishimori , Tomoyuki Obuchi , Antonello Scardicchio

We report on the results of the first 3D SPH simulation of massive, gravitationally unstable protoplanetary disks with radiative transfer. We adopt a flux-limited diffusion scheme justified by the high opacity of most of the disk. The…

Astrophysics · Physics 2009-11-11 Lucio Mayer , Graeme Lufkin , Thomas Quinn , James Wadsley

The spectral index $s$ of particles diffusively accelerated in a relativistic shock depends on the unknown angular diffusion function $\mathcal{D}$, which itself depends on the particle distribution function $f$ if acceleration is…

High Energy Astrophysical Phenomena · Physics 2022-09-21 Yotam Nagar , Uri Keshet
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