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Related papers: Orbit-based dynamical models of the Sculptor dSph …

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We have developed a spherically symmetric dynamical model of a dwarf spheroidal galaxy using the Schwarzschild method. This type of modelling yields constraints both on the total mass distribution (e.g. enclosed mass and scale radius) as…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Maarten A. Breddels , Amina Helmi , R. C. E. van den Bosch , G. van de Ven , G. Battaglia

We analyze three epochs of HST imaging over 20 years for the Sculptor dwarf spheroidal galaxy, measuring precise proper motions for 119 stars and combining them with 1760 existing line-of-sight velocities. This catalog yields the first…

We present a new discrete chemo-dynamical axisymmetric modeling technique, which we apply to the dwarf spheroidal galaxy Sculptor. The major improvement over previous Jeans models is that realistic chemical distributions are included…

Astrophysics of Galaxies · Physics 2016-09-07 Ling Zhu , Glenn van de Ven , Laura L. Watkins , Lorenzo Posti

We test the ability of Schwarzschild's orbit superposition method in measuring the mass content, scale radius and shape of a flattened dwarf spheroidal galaxy. Until now, most dynamical model efforts have assumed that dwarf spheroidal…

Astrophysics of Galaxies · Physics 2019-12-11 Jorrit H. J. Hagen , Amina Helmi , Maarten A. Breddels

The Sculptor dwarf spheroidal galaxy contains two distinct stellar populations: one metal-rich and the other metal-poor. Several authors have argued that in order for these two populations to reside in the same gravitational potential, the…

Astrophysics of Galaxies · Physics 2019-09-25 Louis E. Strigari , Carlos S. Frenk , Simon D. M. White

Dwarf spheroidal (dSph) galaxies are believed to be strongly dark matter dominated and thus are considered perfect objects to study dark matter distribution and test theories of structure formation. They possess resolved, multiple stellar…

Astrophysics of Galaxies · Physics 2022-03-16 Klaudia Kowalczyk , Ewa L. Lokas

Dwarf galaxies satellite of the Milky Way are excellent laboratories for testing dark matter (DM) models and baryonic feedback implementation in simulations. The Sculptor 'classical' dwarf spheroidal galaxy, a system with two distinct…

We present a new study concerning the application of the Schwarzschild orbit superposition method to model spherical galaxies. The method aims to recover the mass and the orbit anisotropy parameter profiles of the objects using measurements…

Astrophysics of Galaxies · Physics 2017-07-26 Klaudia Kowalczyk , Ewa L. Lokas , Monica Valluri

We present a full dynamical model of the Fornax dwarf spheroidal galaxy obtained with the spherically symmetric Schwarzschild orbit superposition method applied to the largest kinematic data set presently available. We modelled the total…

Astrophysics of Galaxies · Physics 2018-11-28 Klaudia Kowalczyk , Andrés del Pino , Ewa L. Lokas , Monica Valluri

I review the current status of dynamical modelling of dwarf spheroidal galaxies focusing on estimates of their dark matter content. Starting with the simplest methods using the velocity dispersion profiles I discuss the inherent issues of…

Astrophysics of Galaxies · Physics 2020-05-20 Ewa L. Lokas

In our previous work we confirmed the reliability of the spherically symmetric Schwarzschild orbit-superposition method to recover the mass and velocity anisotropy profiles of spherical dwarf galaxies. Here we investigate the effect of its…

Astrophysics of Galaxies · Physics 2018-03-14 Klaudia Kowalczyk , Ewa L. Lokas , Monica Valluri

We present VLT/FLAMES spectroscopic observations (R~6500) in the CaII triplet region for 470 probable kinematic members of the Sculptor (Scl) dwarf spheroidal galaxy. The accurate velocities (+- 2 km/s) and large area coverage of Scl allow…

Astrophysics · Physics 2009-11-13 G. Battaglia , A. Helmi , E. Tolstoy , M. Irwin , V. Hill , P. Jablonka

In previous work we have presented Schwarzschild models of the Sculptor dSph, demonstrating that this system could be embedded in dark matter halos that are either cusped or cored. Here we show that the non-parametric distribution function…

Astrophysics of Galaxies · Physics 2015-06-19 Maarten A. Breddels , Amina Helmi

We introduce a novel implementation of orbit-based (or Schwarzschild) modeling that allows dark matter density profiles to be calculated non-parametrically in nearby galaxies. Our models require no assumptions to be made about velocity…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 John R. Jardel , Karl Gebhardt , Maximilian Fabricius , Niv Drory , Michael J. Williams

Dwarf spheroidal galaxies (dSphs) appear to be some of the most dark matter dominated objects in the Universe. Their dynamical masses are commonly derived using the kinematics of stars under the assumption of equilibrium. However, these…

Astrophysics of Galaxies · Physics 2019-07-02 G. Iorio , C. Nipoti , G. Battaglia , A. Sollima

This article describes the Schwarzschild orbit superposition method. It is the state-of-the-art dynamical modelling tool for early-type galaxies. Tests with analytic models show that masses and orbital anisotropies of not too face-on…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Jens Thomas

We evaluate the capabilities of Schwarzschild's orbit-superposition method by applying it to galaxies from the large scale, high resolution Illustris simulation. Nine early-type galaxies with a range of triaxiality are selected, and we…

Astrophysics of Galaxies · Physics 2019-05-01 Yunpeng Jin , Ling Zhu , R. J. Long , Shude Mao , Dandan Xu , Hongyu Li , Glenn van de Ven

We apply the Schwarzschild orbit superposition method to mock data in order to investigate the accuracy of recovering the profile of the orbit anisotropy. The mock data come from four numerical realizations of dark matter haloes with well…

Astrophysics of Galaxies · Physics 2015-12-24 Klaudia Kowalczyk , Ewa L. Lokas , Monica Valluri

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

A number of dwarf spheroidal (dSph) galaxies are known to contain a more extended, metal-poor population with a flattish velocity dispersion profile, and a more concentrated, metal-rich population with a velocity dispersion declining with…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 N. C. Amorisco , N. W. Evans
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