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We have compiled a new sample of 240 halo objects with accurate distance and radial velocity measurements, including globular clusters, satellite galaxies, field blue horizontal branch stars and red giant stars from the Spaghetti survey.…

Dark matter N-body simulations suggest that the velocity distribution of dark matter is anisotropic. In this work we employ a mass model for the Milky Way whose parameters are determined from a fit to kinematical data. Then we adopt an…

宇宙学与河外天体物理 · 物理学 2015-06-17 Nassim Bozorgnia , Riccardo Catena , Thomas Schwetz

We use distant Blue Horizontal Branch stars with Galactocentric distances 16 < r/kpc < 48 as kinematic tracers of the Milky Way dark halo. We model the tracer density as an oblate, power-law embedded within a spherical power-law potential.…

星系天体物理 · 物理学 2015-06-04 A. J. Deason , V. Belokurov , N. W. Evans , J. H. An

Dark Matter (DM) direct detection experiments usually assume the simplest possible 'Standard Halo Model' for the Milky Way (MW) halo in which the velocity distribution is Maxwellian. This model assumes that the MW halo is an isotropic,…

宇宙学与河外天体物理 · 物理学 2014-04-02 Mattia Fornasa , Anne M. Green

Modeling the Milky Way stellar halo requires well-determined density and velocity anisotropy profiles. However, it has been challenging to gather a large sample of stars with six-dimensional data that extend beyond 40 kpc to map the outer…

We re-analyse the velocity-dispersion profile sigma(r) at radii r>10 kpc in the Galactic stellar halo, recently derived by Battaglia et al. (2005), who concluded that, for constant velocity anisotropy of the tracers, these data rule out a…

天体物理学 · 物理学 2009-11-11 Walter Dehnen , Dean McLaughlin , Jalpesh Sachania

The velocity anisotropy of particles inside dark matter (DM) haloes is an important physical quantity, which is required for the accurate modelling of mass profiles of galaxies and clusters of galaxies. It is typically measured using the…

宇宙学与河外天体物理 · 物理学 2015-06-15 Radoslaw Wojtak , Stefan Gottloeber , Anatoly Klypin

We measure the three components of velocity dispersion, $\sigma_{R},\sigma_{\theta},\sigma_{\phi}$, for stars within 6 < R < 30 kpc of the Milky Way using a new radial velocity sample from the MMT telescope. We combine our measurements with…

星系天体物理 · 物理学 2015-11-11 Charles King , Warren R. Brown , Margaret J. Geller , Scott J. Kenyon

Numerous numerical studies indicate that dark matter halos show an almost universal radial density profile. The origin of the profile is still under debate. We investigate this topic and pay particular attention to the velocity dispersion…

天体物理学 · 物理学 2009-11-10 M. Hoeft , J. P. Muecket , S. Gottloeber

Using a generalized self-similar secondary infall model, which accounts for tidal torques acting on the halo, we analyze the velocity profiles of halos in order to gain intuition for N-body simulation results. We analytically calculate the…

宇宙学与河外天体物理 · 物理学 2010-12-23 Phillip Zukin , Edmund Bertschinger

We investigate the relationship between a dark matter halo's mass profile and measures of the velocity dispersion of kinematic tracers within its gravitational potential. By predicting the scaling relation of the halo mass with the aperture…

星系天体物理 · 物理学 2024-03-13 Andrew Sullivan , Chris Power , Connor Bottrell

Using cosmological N-body simulations we study the line-of-sight velocity distribution of dark matter haloes focusing on the lowest-order even moments, dispersion and kurtosis, and their application to estimate the mass profiles of…

天体物理学 · 物理学 2009-11-13 Radoslaw Wojtak , Ewa L. Lokas , Stefan Gottloeber , Gary A. Mamon

We present a spectroscopic sample of 910 distant halo stars from the Hypervelocity Star survey from which we derive the velocity dispersion profile of the Milky Way halo. The sample is a mix of 74% evolved horizontal branch stars and 26%…

星系天体物理 · 物理学 2010-07-22 Warren R. Brown , Margaret J. Geller , Scott J. Kenyon , Antonaldo Diaferio

Rates for detection of weakly-interacting massive-particle (WIMP) dark matter are usually carried out assuming the Milky Way halo is an isothermal sphere. However, it is possible that our halo is not precisely spherical; it may have some…

高能物理 - 唯象学 · 物理学 2010-11-30 Marc Kamionkowski , Ali Kinkhabwala

Fast radio bursts offer the opportunity to place new constraints on the mass and density profile of hot and ionized gas in galactic haloes. We test here the X-ray emission and dispersion measure predicted by different gas profiles for the…

星系天体物理 · 物理学 2020-06-03 Laura C. Keating , Ue-Li Pen

Using cosmological $N$-body simulations of dark matter haloes, we study the effects of non-sphericity, substructure and streaming motions in reproducing the structure and internal kinematics of clusters of galaxies from kinematical…

天体物理学 · 物理学 2009-11-10 Teresa Sanchis , Ewa L. Lokas , Gary A. Mamon

We introduce a very simple model of a dark halo. It is a close relative of Hernquist's model, being generated by the same transformation but this time applied to the logarithmic potential rather than the point mass. The density is…

星系天体物理 · 物理学 2015-06-22 N. W. Evans , A. A. Williams

Using cosmological N-body simulations we study the radial velocity distribution in dark matter haloes focusing on the lowest-order even moments, dispersion and kurtosis. We determine the properties of ten massive haloes in the simulation…

天体物理学 · 物理学 2009-11-10 Radoslaw Wojtak , Ewa L. Lokas , Stefan Gottloeber , Gary A. Mamon

Determining the velocity distribution of halo stars is essential for estimating the mass of the Milky Way and for inferring its formation history. Since the stellar halo is a dynamically hot system, the velocity distribution of halo stars…

星系天体物理 · 物理学 2017-06-14 Kohei Hattori , Monica Valluri , Sarah R. Loebman , Eric F. Bell

We model the fastest moving (v_tot > 300 km/s) local (D < 3 kpc) halo stars using cosmological simulations and 6-dimensional Gaia data. Our approach is to use our knowledge of the assembly history and phase-space distribution of halo stars…

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