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Related papers: Gravitational Lensing by Dark Matter Caustics

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In the frame of indirect dark matter searches we investigate the flux of high-energy $\gamma$-ray photons produced by annihilation of dark matter in caustics within our Galaxy under the hypothesis that the bulk of dark matter is composed of…

Astrophysics · Physics 2009-11-11 Lidia Pieri , Enzo Branchini

Well known scaling laws among the structural properties of the dark and the luminous matter in disc systems are too complex to be arisen by two inert components that just share the same gravitational field. This brings us to critically…

Astrophysics of Galaxies · Physics 2020-03-10 Paolo Salucci , Nicola Turini

Gravitational lensing of distant objects caused by gravitational tidal forces from inhomogeneities in the universe is weak in most cases, but it is noticed that it gives a great deal of information about the universe, especially regarding…

Astrophysics · Physics 2008-11-26 Kenji Tomita , Premana Premadi , Takahiro T. Nakamura

This work develops and explores a quantum-based theory which enables the nature and origin of cold dark matter (CDM) to be understood without need to introduce exotic particles. The quantum approach predicts the existence of certain…

Astrophysics · Physics 2009-03-02 A. D. Ernest

While the $\Lambda$CDM model succeeds on large scales, its validity on smaller scales remains uncertain. Recent works suggest that non-halo dark matter structures, such as filaments and walls, could significantly influence gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-21 Baptiste Jego , Giulia Despali , Tamara Richardson , Jens Stücker

Theoretical models of self-interacting dark matter represent a promising answer to a series of open problems within the so-called collisionless cold dark matter (CCDM) paradigm. In case of asymmetric dark matter, self-interactions might…

High Energy Astrophysical Phenomena · Physics 2017-08-02 Andrea Maselli , Pantelis Pnigouras , Niklas Gønlund Nielsen , Chris Kouvaris , Kostas D. Kokkotas

We point out that current constraints on dark matter imply only that the majority of dark matter is cold and collisionless. A subdominant fraction of dark matter could have much stronger interactions. In particular, it could interact in a…

High Energy Physics - Phenomenology · Physics 2013-08-06 JiJi Fan , Andrey Katz , Lisa Randall , Matthew Reece

Based on observed rotation curves of galaxies and theoretical simulations of dark matter halos, there are reasons for believing that at least three different types of dark matter halos exist in the Universe classified by their masses M and…

Astrophysics · Physics 2009-11-07 Li-Xin Li , Jeremiah P. Ostriker

This paper reviews statistical methods recently developed to reconstruct and analyze dark matter mass maps from weak lensing observations. The field of weak lensing is motivated by the observations made in the last decades showing that the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 S. Pires , J. -L. Starck , A. Refregier

A galaxy cluster acts as a cosmic telescope over background galaxies but also as a cosmic microscope of the lens imperfections. The diverging magnification of lensing caustics enhances the microlensing effect of substructure present within…

Well known scaling laws among the structural properties of the dark and the luminous matter in disc systems are too complex to be arisen by two inert components that just share the same gravitational field. This brings us to critically…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-28 Paolo Salucci , Nicola Turini , Chiara Di Paolo

Formation of sub-galactic halos is suppressed in warm dark matter (WDM) model due to thermal motion of WDM particles. This may provide a natural resolution to some puzzles in standard cold dark matter (CDM) theory such as the cusped density…

Astrophysics · Physics 2009-11-06 Yan-Jie Xue , Xiang-Ping Wu

If dark halos are composed of dense gas clouds, as has recently been inferred, then collisions between clouds lead to galaxy evolution. Collisions introduce a core in an initially singular dark matter distribution, and can thus help to…

Astrophysics · Physics 2009-10-30 Mark A. Walker

If dark matter in the form of compact objects comprises a large fraction of the mass of the universe, then gravitational lensing effects on gamma-ray bursts are expected. We utilize BATSE and Ulysses data to search for lenses of different…

Astrophysics · Physics 2009-10-31 G. F. Marani , R. J. Nemiroff , J. P. Norris , K. Hurley , J. T. Bonnell

We present a detailed study of the structural properties of four gravitationally lensed disk galaxies at z=1. Modelling the rotation curves on sub-kpc scales we derive the values for the disk mass, the reference dark matter density and core…

Astrophysics · Physics 2015-05-13 P. Salucci , A. M. Swinbank , A. Lapi , I. Yegorova , R. G. Bower , Ian Smail , G. P. Smith

I argue that the cold dark matter (CDM) model requires that even within a few kpc of the center of a galactic halo a significant fraction (greater than a few percent) of the surface density is contained in substructures with masses > 10^3…

Astrophysics · Physics 2007-05-23 R. Benton Metcalf

In the standard cosmological model, the Universe consists mainly of two invisible substances: vacuum energy with constant mass-density rho_v=\Lambda/(8pi G) (where Lambda is a `cosmological constant' originally proposed by Einstein and G is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Matthew G. Walker , Abraham Loeb

N-body simulations and analytical calculations of the gravitational collapse in an expanding universe predict that halos should form with a diverging inner density profile, the cusp. There are some observational indications that the dark…

Astrophysics · Physics 2009-11-06 Amr El-Zant , Isaac Shlosman , Yehuda Hoffman

The central densities of dark matter (DM) halos are much lower than predicted in cold DM models of structure formation. Confirmation that they have cores with a finite central density would allow us to rule out many popular types of…

Astrophysics · Physics 2009-10-31 J. A. Sellwood

It is now believed that the universe is composed of a small amount of the normal luminous matter, a substantial amount of matter (Cold Dark Matter: CDM) which is non-luminous and a large amount of smooth energy (Dark Energy: DE). Both CDM…

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