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Halo stars orbit within the potential of the Milky Way and hence their kinematics can be used to understand the underlying mass distribution. However, the inferred mass distribution depends sensitively upon assumptions made on the density…

星系天体物理 · 物理学 2015-06-22 Prajwal R. Kafle , Sanjib Sharma , Geraint F. Lewis , Joss Bland-Hawthorn

We present initial results from ``Via Lactea'', the highest resolution simulation to date of Galactic CDM substructure. It follows the formation of a Milky Way-size halo with Mvir=1.8x10^12 Msun in a WMAP 3-year cosmology, using 234 million…

天体物理学 · 物理学 2010-11-05 Juerg Diemand , Michael Kuhlen , Piero Madau

The recent astrometric data of hundreds of millions of stars from Gaia DR3 has allowed a precise determination of the Milky Way rotation curve up to $28$~kpc. The data suggests a rapid decline in the density of dark matter beyond $19$~kpc.…

星系天体物理 · 物理学 2024-02-09 Juan Garcia-Bellido , Michael Hawkins

About one year ago, it was speculated that decaying or annihilating Light Dark Matter (LDM) particles could explain the flux and extension of the 511 keV line emission in the galactic centre. Here we present a thorough comparison between…

天体物理学 · 物理学 2009-11-11 Y. Ascasibar , P. Jean , C. Boehm , J. Knoedlseder

We propose a heuristic model that displays the main features of realistic theories for galaxy bias. We show that the low-order clustering statistics of the dark-matter distribution depend almost entirely on the locations and density…

天体物理学 · 物理学 2011-05-05 J. A. Peacock , R. E. Smith

We discuss the recent Baryon Oscillation Spectroscopic Survey measurement of a rather high bias factor for the host galaxies/haloes of Damped Lyman-alpha Absorbers (DLAs), in the context of our previous modelling of the physical properties…

宇宙学与河外天体物理 · 物理学 2015-11-06 Luke A. Barnes , Martin G. Haehnelt

The shape of the dark matter (DM) halo is key to understanding the hierarchical formation of the Galaxy. Despite extensive efforts in recent decades, however, its shape remains a matter of debate, with suggestions ranging from strongly…

Here we present a kinematic study of the Galactic halo out to a radius of $\sim$ 60 kpc, using 4664 blue horizontal branch (BHB) stars selected from the SDSS/SEGUE survey, to determine key dynamical properties. Using a maximum likelihood…

星系天体物理 · 物理学 2012-12-04 Prajwal R. Kafle , Sanjib Sharma , Geraint F. Lewis , Joss Bland-Hawthorn

Unveiling the 3D shape of the Milky Way's dark-matter halo is critical to understanding its formation history. We created an innovative dynamical model with minimal assumptions on the internal dynamical structures and accommodates a highly…

星系天体物理 · 物理学 2026-02-26 Ling Zhu , Runsheng Cai , Xi Kang , Xiang-Xiang Xue , Chengqun Yang , Lan Zhang , Shude Mao , Chao Liu

The shape and orientation of the Milky Way's dark matter halo remain poorly constrained. Observations of the accreted stellar halo show that it is triaxial and tilted with respect to the disc. If this configuration is long-lived, it can…

星系天体物理 · 物理学 2026-02-18 Adam M. Dillamore , Jason L. Sanders

We present a kinematical study of the outer halo (r_GC approximately 60 to 160 kpc) of the Milky Way based on spectroscopy of 55 RR Lyrae stars obtained with the ESI instrument on the Keck II telescope. Our spectroscopic targets were…

We show that the position of the central dark matter density peak may be expected to differ from the dynamical center of the Galaxy by several hundred parsec. In Eris, a high resolution cosmological hydrodynamics simulation of a realistic…

星系天体物理 · 物理学 2015-06-11 Michael Kuhlen , Javiera Guedes , Annalisa Pillepich , Piero Madau , Lucio Mayer

Dwarf galaxies have a wide variety of structures, such as dark matter (DM) distribution, stellar-to-halo mass ratio, and stellar density. Recent high-resolution simulations have shown a variety of stellar-to-halo mass ratios for dwarf…

星系天体物理 · 物理学 2026-01-21 Katsuhiro Kaneko , Takayuki R. Saitoh , Yutaka Hirai , Michiko S. Fujii

Milky Way's hot gaseous halo extends up to the Galactic virial radius ($\sim 200$ kpc) and contains a significant component of baryon mass of the Galaxy. The halo properties can be constrained from X-ray spectroscopic observations and from…

星系天体物理 · 物理学 2022-02-18 Nickolay Martynenko

The gravitational interaction between the Milky Way (MW) and the Large Magellanic Cloud (LMC) perturbs the MW halo's density and kinematics, encoding information about both galaxies' masses and structures. We present a suite of 2,848…

星系天体物理 · 物理学 2025-07-08 Yanjun Sheng , Yuan-Sen Ting , Xiang-Xiang Xue

Recent studies have suggested that the Milky Way (MW)'s Dark Matter (DM) halo may be significantly tilted with respect to its central stellar disk, a feature that might be linked to its formation history. In this work, we demonstrate a…

星系天体物理 · 物理学 2022-10-28 Nondh Panithanpaisal , Robyn E. Sanderson , Arpit Arora , Emily C. Cunningham , Jay Baptista

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

Based on the observed paucity of the dwarf spheroidal (dSph) satellites of the Milky Way at small Galactocentric distances, we put forward the hypothesis that subsequent to the formation of the Milky Way and its satellites, those dSphs that…

天体物理学 · 物理学 2008-11-26 R. Cowsik , Charu Ratnam , Pijushpani Bhattacharjee , Subhabrata Majumdar

We study the distribution function (DF) of dark matter particles in haloes of mass range 10^{14}--10^{15}\Msun. In the numerical part of this work we measure the DF for a sample of relaxed haloes formed in the simulation of a standard…

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

A parameterized model of the mass distribution within the Milky Way is fitted to the available observational constraints. The most important single parameter is the ratio of the scale length R_d* of the stellar disk to R0. The disk and…

天体物理学 · 物理学 2020-11-25 Walter Dehnen , James Binney