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Related papers: Action-based models for dwarf spheroidal galaxies …

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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

A new class of models of stellar discs is introduced and used to build a self-consistent model of our Galaxy. The model is defined by the parameters that specify the action-based distribution functions (DFs) f(J) of four stellar discs…

Astrophysics of Galaxies · Physics 2023-01-25 James Binney , Eugene Vasiliev

We develop a flexible set of action-based distribution functions (DFs) for stellar haloes. The DFs have five free parameters, controlling the inner and outer density slope, break radius, flattening and anisotropy respectively. The DFs…

Astrophysics of Galaxies · Physics 2015-09-30 A. A. Williams , N. W. Evans

We present an approach to the design of distribution functions that depend on the phase-space coordinates through the action integrals. The approach makes it easy to construct a dynamical model of a given stellar component. We illustrate…

Astrophysics of Galaxies · Physics 2015-06-23 Lorenzo Posti , James Binney , Carlo Nipoti , Luca Ciotti

The local group dwarf spheroidal galaxies (LG dSphs) are among the most promising astrophysical targets for probing the small scale structure of dark matter (DM) subhalos. We describe a method for testing the correspondence between proposed…

Astrophysics of Galaxies · Physics 2020-12-09 Sasha Brownsberger , Lisa Randall

Dwarf spheroidal galaxies (dSphs) are prime laboratories for studying dark matter (DM) and the black hole demographics in the low-mass regime. These systems are also often flattened; nevertheless most studies rely on spherical models,…

Astrophysics of Galaxies · Physics 2026-04-29 R. Pascale , G. Battaglia , J. M. Arroyo-Polonio , E. Vasiliev , C. Nipoti , G. F. Thomas

We provide a family of action-based distribution functions (DFs) for the double-power law family of densities often used to model galaxies. The DF itself is a double-power law in combinations of the actions, and reduces to the known limits…

Astrophysics of Galaxies · Physics 2015-06-23 A. A. Williams , N. W. Evans

Galaxy models comprising several components (including dark matter) that are bound by the self-consistently generated gravitational field are readily constructed from distribution functions (DFs) that are analytic functions of the action…

Astrophysics of Galaxies · Physics 2026-05-20 James Binney

In the Fornax dwarf spheroidal galaxy the globular clusters are distributed widely, without any significant central concentration. Oh et al. pointed out that such a distribution is paradoxical: dynamical friction effects estimated using…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-12 Ramanath Cowsik , Kasey Wagoner , Emanuele Berti , Amit Sircar

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 structure and dark matter halo core properties of dwarf spheroidal galaxies (dSphs) are investigated. A double-isothermal model of an isothermal stellar system, embedded in an isothermal dark halo core provides an excellent fit to the…

Astrophysics of Galaxies · Physics 2015-06-23 Andreas Burkert

The analytical phase-space distribution function (DF) of spherical self--consistent galaxy (or cluster) models, embedded in a dark matter halo, where both density distributions follow the Hernquist profile, with different total masses and…

Astrophysics · Physics 2009-10-28 Luca Ciotti

In this work, we present an action-based dynamical equilibrium model to constrain the phase-space distribution of stars in the stellar halo, present-day dark matter distribution, and the total mass distribution in M31-like galaxies. The…

Astrophysics of Galaxies · Physics 2023-07-20 Paula Gherghinescu , Payel Das , Robert J. J. Grand , Matthew D. A. Orkney

We address an issue that arises when self-consistently flattened dynamical stellar systems are constructed by adopting a distribution function (DF) that depends on the action integrals. The velocity distribution at points on the symmetry…

Astrophysics of Galaxies · Physics 2019-07-24 Raffaele Pascale , James Binney , Carlo Nipoti

This paper introduces a new two-parameter family of dwarf spheroidal (dSph) galaxy models. The density distribution has a Plummer profile and falls like the inverse fourth power of distance in projection, in agreement with the star-count…

Astrophysics · Physics 2009-11-07 M. I. Wilkinson , J. Kleyna , N. W. Evans , G. Gilmore

We use controlled $N$-body experiments to study the dynamical evolution of dwarf spheroidal galaxies (dSphs) embedded in dark-matter (DM) haloes containing a large population of dark subhaloes. We show that stellar orbits subject to…

Astrophysics of Galaxies · Physics 2026-04-28 Jorge Peñarrubia , Ethan O. Nadler

Dark matter (DM) subhalos offer critical tests of cosmological models through their abundance and properties, yet most remain undetectable due to their lack of stars. We investigate whether their presence leaves measurable imprints on the…

Astrophysics of Galaxies · Physics 2026-01-14 Eduardo Vitral , Jorge Peñarrubia , Matthew G. Walker

It is now established that several of the Local Group dwarf Spheroidal galaxies (dSphs) have large mass-to-light ratios. We consider the possibility that the dark matter in the halos of dSphs is composed of massive black holes with masses…

Astrophysics · Physics 2009-11-10 Shoko Jin , Jeremiah P. Ostriker , Mark I. Wilkinson

This paper investigates spheroidal galaxies comprising a self-interacting dark matter halo (SIDM) plus de Vaucouleurs stellar distribution. These are coupled only via their shared gravitational field, which is computed consistently from the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Curtis J. Saxton

We present nearly self-consistent stellar-halo models of the Fornax dwarf spheroidal galaxy associated with the Milky Way galaxy. Such galaxies are dominated by dark matter and have almost no gas in the system. Therefore, they are excellent…

Astrophysics of Galaxies · Physics 2021-05-25 Galina Shchelkanova , Kohei Hayashi , Sergei Blinnikov
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