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We forecast parameter uncertainties on the mass profile of a typical Milky Way dwarf spheroidal (dSph) galaxy using the spherical Jeans Equation and Fisher matrix formalism. We show that radial velocity measurements for 1000 individual…

星系天体物理 · 物理学 2021-12-13 Juan Guerra , Marla Geha , Louis E. Strigari

Dark matter comprises the bulk of the matter in the universe but its particle nature and cosmological origin remain mysterious. Knowledge of the dark matter density distribution in the Milky Way Galaxy is crucial to both our understanding…

We show that measuring the proper motion of ${{\sim 2000}}$ stars within a dwarf galaxy, with an uncertainty of 1 km/s at most, can establish whether the Dark Matter (DM) density profile of the dwarf has a central core or cusp. We derive…

星系天体物理 · 物理学 2022-08-31 Ivan de Martino , Antonaldo Diaferio , Luisa Ostorero

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…

天体物理学 · 物理学 2009-11-07 M. I. Wilkinson , J. Kleyna , N. W. Evans , G. Gilmore

The fact that dark matter (DM), thus far, has revealed itself only on scales of galaxies and larger, again thrusts onto astrophysics the opportunity and the responsibility to confront the age old mystery "What is the nature of matter?" By…

For nearly 40 years, dark matter has been widely assumed to be cold and collisionless. Cold dark matter models make fundamental predictions for the behavior of dark matter on small (<10 kpc) scales. These predictions include cuspy density…

We analyze four epochs of HST imaging over 18 years for the Draco dwarf spheroidal galaxy. We measure precise proper motions (PMs) for hundreds of stars and combine these with existing line-of-sight (LOS) velocities. This provides the first…

Precision astrometry offers a way to probe new physics. By measuring the angular position of light sources at unprecedented precision, astrometry could probe minuscule fluctuations of underlying spacetime. This work explores the possibility…

高能物理 - 唯象学 · 物理学 2024-06-07 Hyungjin Kim

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…

Low luminosity dwarf galaxies provide stringent constraints on the nature of dark matter. Establishing these constraints depends on precise kinematic measurements of individual stars. In this overview for non-specialists, we describe…

宇宙学与河外天体物理 · 物理学 2021-12-10 J. D. Simon , M. Geha

The nature of dark matter is one of the outstanding questions of astrophysics. The internal motions of member stars reveal that the lowest luminosity galaxies in the Local Group are the most dark-matter dominated. New large datasets allow…

天体物理学 · 物理学 2009-11-13 Rosemary F. G. Wyse , Gerard Gilmore

While galaxy rotation curves provide one of the most powerful methods for measuring dark matter profiles in the inner regions of rotation-supported galaxies, at the dwarf scale there are factors that can complicate this analysis. Given the…

Dark-matter-only simulations predict that dark matter halos have cusp-like inner density profiles, while observations of low-mass galaxies have found a range of inner slopes that are typically much shallower. It is still not well…

Astrometry -- the precise measurement of positions and motions of celestial objects -- has emerged as a promising avenue for characterizing the dark matter population in our Galaxy. By leveraging recent advances in simulation-based…

宇宙学与河外天体物理 · 物理学 2022-01-06 Siddharth Mishra-Sharma

The distribution of dark matter in dwarf galaxies can have important implications on our understanding of galaxy formation as well as the particle physics properties of dark matter. However, accurately characterizing the dark matter content…

宇宙学与河外天体物理 · 物理学 2021-09-01 Laura J. Chang , Lina Necib

A Bayesian likelihood analysis of the stellar density profile shapes of several dark matter dominated Galactic dwarf spheroidal galaxies (dSphs) has been completed. This analysis indicates that the inner power law, \rho \propto r^{-\gamma},…

天体物理学 · 物理学 2007-05-23 Kris Sigurdson , Neil Turok

There has been a vast recent improvement in photometric and kinematic data for star clusters, Ultra Compact dwarfs, galactic nuclei, and local dSph galaxies, with Subaru contributing substantially to the photometric studies in particular.…

Gamma-ray searches for dark matter annihilation and decay in dwarf galaxies rely on an understanding of the dark matter density profiles of these systems. Conversely, uncertainties in these density profiles propagate into the derived…

宇宙学与河外天体物理 · 物理学 2015-03-12 Alex Geringer-Sameth , Savvas M. Koushiappas , Matthew Walker

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…

星系天体物理 · 物理学 2015-06-23 Andreas Burkert

We present a synthesis of recent photometric and kinematic data for several of the most dark-matter dominated galaxies. There is a bimodal distribution in half-light radii, with stable star clusters always being smaller than $\sim30$pc,…

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