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Related papers: Infall caustics in dark matter halos?

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We have found that the phase-space of a dark matter particles assembling a galactic halo in cosmological N-body simulations has well defined fine grained structure. Recently accreted particles form distinctive velocity streams with high…

Astrophysics of Galaxies · Physics 2015-06-11 K. Dolag , A. D. Dolgov , I. I. Tkachev

Cold dark matter haloes are populated by caustics, which are yet to be resolved in N-body simulations or observed in the Universe. Secondary infall model provides a paradigm for the study of caustics in "typical" haloes assuming that they…

Astrophysics · Physics 2009-11-13 Roya Mohayaee , Sergei Shandarin , Joseph Silk

Caustics are high-density structures that form frequently in collisionless media. Under self-gravity, cold dark matter flows focus onto caustics which are yet to be resolved in numerical simulations and or observed in the real world. If…

Astrophysics · Physics 2008-11-26 Raphael Gavazzi , Roya Mohayaee , Bernard Fort

Caustics are formally singular structures, with infinite density, that form in collisionless media. The non-negligible velocity dispersion of dark matter particles renders their density finite. We evaluate the maximum density of the…

The late infall of cold dark matter onto an isolated galaxy such as our own produces flows with definite velocity vectors at any physical point in the galactic halo. It also produces caustics which are places where the dark matter density…

Astrophysics · Physics 2016-11-03 P. Sikivie , W. Kinney

We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…

The spectrum of cold dark matter particles on Earth is expected to have peaks in velocity space associated with particles which are falling onto the Galaxy for the first time and with particles which have fallen in and out of the Galaxy…

Astrophysics · Physics 2010-11-30 P. Sikivie , I. I. Tkachev , Yun Wang

We simulate the growth of isolated dark matter haloes from self-similar and spherically symmetric initial conditions. Our N-body code integrates the geodesic deviation equation in order to track the streams and caustics associated with…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Mark Vogelsberger , Simon D. M. White , Roya Mohayaee , Volker Springel

Dark matter density is formally infinite at the location of caustic surfaces, where dark matter sheet folds in phase space. The caustics separate multi-stream regions with different number of streams. Volume elements change the parity by…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 Segei F. Shandarin

We examine the properties of dark matter halos within a rich galaxy cluster using a high resolution simulation that captures the cosmological context of a cold dark matter universe. The mass and force resolution permit the resolution of 150…

Astrophysics · Physics 2009-10-30 Sebastiano Ghigna , Ben Moore , Fabio Governato , George Lake , Thomas Quinn , Joachim Stadel

Motivated by the recent direct detection of cosmological gas infall, we develop an analytical model for calculating the mean density profile around an initial overdensity that later forms a dark matter halo. We account for the problem of…

Astrophysics · Physics 2009-11-07 Rennan Barkana

Cold dark matter haloes are populated by high-density structures with sharply-peaked profiles known as caustics which have not yet been resolved by 3-dimensional numerical simulations. Here, we derive semi-analytic expressions for the…

Astrophysics · Physics 2009-11-10 Roya Mohayaee , Sergei Shandarin

We obtain predictions for the properties of cold dark matter annihilation radiation using high resolution hydrodynamic zoom-in cosmological simulations of Milky Way-like galaxies (APOSTLE project) carried out as part of the "Evolution and…

The late infall of cold dark matter onto an isolated galaxy, such as our own, produces streams and caustics in its halo. The outer caustics are topological spheres whereas the inner caustics are rings. The self-similar model of galactic…

Astrophysics · Physics 2009-11-07 P. Sikivie

Much recent discussion about dark matter has been centered on two seemingly independent problems: the abundance of substructure in dark matter halos, and the cuspiness of the halos' inner density profile. We explore possible connections…

Astrophysics · Physics 2009-11-10 Chung-Pei Ma , Michael Boylan-Kolchin

Light non-relativistic components of the galactic dark matter halo elude direct detection constraints because they lack the kinetic energy to create an observable recoil. However, cosmic-rays can upscatter dark matter to significant…

High Energy Physics - Phenomenology · Physics 2021-10-26 Nicole F. Bell , James B. Dent , Bhaskar Dutta , Sumit Ghosh , Jason Kumar , Jayden L. Newstead , Ian M. Shoemaker

We use a cosmological simulation of the Local Group to make quantitative and speculative predictions for direct detection experiments. Cold dark matter (CDM) halos form via a complex series of mergers, accretion events and violent…

The late infall of cold dark matter onto our galaxy produces discrete flows and caustics in its halo. The recently discovered ring of stars near galactocentric distance 20 kpc and a series of sharp rises in the Milky Way rotation curve are…

Astrophysics · Physics 2014-10-13 Pierre Sikivie

We develop a theoretical framework for describing the hierarchical structure of the phase space of cold dark matter haloes, due to gravitationally bound substructures. Because it includes the full hierarchy of the cold dark matter initial…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Niayesh Afshordi , Roya Mohayaee , Edmund Bertschinger

Dark matter caustics are small scale, high density structures believed to exist in galaxies like ours. If the dark matter consists of Weakly Interacting Massive Particles, these caustics may be detected by means of the gamma rays produced…

Astrophysics · Physics 2008-12-18 Aravind Natarajan , Pierre Sikivie
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