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The properties of the analitycal phase--space distribution function of two-component spherical self-consistent galaxy models, where one density distribution follows the Hernquist profile, and the other a gamma=0 model, with different total…

Astrophysics · Physics 2007-05-23 L. Ciotti

Under the separability assumption on the augmented density, a distribution function can be always constructed for a spherical population with the specified density and anisotropy profile. Then, a question arises, under what conditions the…

Mathematical Physics · Physics 2012-01-31 J. An

A new family of self-consistent DF-based models of stellar systems is explored. The stellar component of the models is described by a distribution function (DF) depending on the action integrals, previously used to model the Fornax dwarf…

Astrophysics of Galaxies · Physics 2019-06-26 Raffaele Pascale , James Binney , Carlo Nipoti , Lorenzo Posti

We computed flat rotation curves from scalar-tensor theories in their weak field limit. Our model, by construction, fits a flat rotation profile for velocities of stars. As a result, the form of the scalar field potential and DM…

Astrophysics · Physics 2008-11-26 Jorge L. Cervantes-Cota , M. A. Rodriguez-Meza , Dario Nunez

Enhanced diffusion, which describes the accelerated spread of passive scalars due to the interaction between advection and molecular diffusion, has been extensively studied in simplified geometries, such as uniform shear and radial flows.…

Analysis of PDEs · Mathematics 2024-11-04 Rômulo Damasclin Chaves dos Santos , Jorge Henrique de Oliveira Sales

We investigate in massive early-type galaxies the variation of their two-dimensional central fraction of dark over total mass and dark matter density as a function of stellar mass, central stellar velocity dispersion, effective radius, and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Claudio Grillo

We study the total mass-density profile for a sample of 14 fast-rotator early-type galaxies (stellar masses $10.2<\log M_\ast/M_\odot<11.7$). We combine observations from the SLUGGS and Atlas3D surveys to map out the stellar kinematics in…

Galaxies and the dark matter halos that host them are not spherically symmetric, yet spherical symmetry is a helpful simplifying approximation for idealised calculations and analysis of observational data. The assumption leads to an exact…

Astrophysics of Galaxies · Physics 2016-01-29 Andrew Pontzen , Justin Read , Romain Teyssier , Fabio Governato , Alessia Gualandris , Nina Roth , Julien Devriendt

Maximum disk mass models fitted to galaxy rotation curves are used to show that dark matter (DM) halos in late-type and dwarf spheroidal (dSph) galaxies satisfy well defined scaling laws. Halos in less luminous galaxies have smaller core…

Astrophysics · Physics 2007-05-23 John Kormendy , K. C. Freeman

Scattering transforms are a new type of summary statistics recently developed for the study of highly non-Gaussian processes, which have been shown to be very promising for astrophysical studies. In particular, they allow one to build…

Instrumentation and Methods for Astrophysics · Physics 2024-11-22 Louise Mousset , Erwan Allys , Matthew A. Price , Jonathan Aumont , Jean-Marc Delouis , Ludovic Montier , Jason D. McEwen

Stellar and gas kinematics of galaxies are a sensitive probe of the dark matter distribution in the halo. The popular fuzzy dark matter models predict the peculiar shape of density distribution in galaxies: specific dense core with sharp…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-07 Mariia Khelashvili , Anton Rudakovskyi , Sabine Hossenfelder

We present new dynamical models of dwarf spheroidal galaxies (dSphs) in which both the stellar component and the dark halo are described by analytic distribution functions that depend on the action integrals. In their most general form…

Astrophysics of Galaxies · Physics 2018-08-01 Raffaele Pascale , Lorenzo Posti , Carlo Nipoti , James Binney

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

We investigate the connection between the morphology and internal kinematics of the stellar component of central galaxies with mass $M_\star > {10}^{9.5} {\rm M}_\odot$ in the EAGLE simulations. We compare several kinematic diagnostics…

We study the total density distribution in the central regions (~ 1 effective radius, $R_e$) of early-type galaxies (ETGs), using data from SPIDER and $\rm ATLAS^{3D}$. Our analysis extends the range of galaxy stellar mass ($M_{\star}$)…

Astrophysics of Galaxies · Physics 2015-06-22 C. Tortora , F. La Barbera , N. R. Napolitano , A. J. Romanowsky , I. Ferreras , R. R. de Carvalho

This paper uses the definition of complexity for a static spherically symmetric spacetime and extends it to the case of charged distribution. We formulate the Einstein-Maxwell field equations corresponding to the anisotropic interior and…

General Relativity and Quantum Cosmology · Physics 2023-06-02 M. Sharif , Tayyab Naseer

We present an innovative approach to the methodology of dynamical modelling, allowing practical reconstruction of the underlying dark matter mass without assuming both the density and anisotropy functions. With this, the mass-anisotropy…

In this paper we calculate the density profiles of virialized halos both in the case of structure evolving hierarchically from a scale-free Gaussian delta-field having a power spectrum P(k)=A k^n in a Omega=1 Universe and in the case of the…

Astrophysics · Physics 2007-05-23 A. Del Popolo , M. Gambera , E. Recami , E. Spedicato

We present a new method of constraining the mass and velocity anisotropy profiles of galaxy clusters from kinematic data. The method is based on a model of the phase space density which allows the anisotropy to vary with radius between two…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Radoslaw Wojtak , Ewa L. Lokas , Gary A. Mamon , Stefan Gottloeber

A simple algorithm is presented for the calculation of the projected line-of-sight velocity profiles (VPs) of non-rotating anisotropic spherical stellar dynamical models with a phase-space distribution function of the Osipkov-Merritt type.…

Astrophysics · Physics 2015-06-24 C. M. Carollo , P. T. de Zeeuw , R. P. van der Marel
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