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The distribution of dark matter at the galactic center, crucial for indirect searches, remains uncertain. In particular, in the vicinity of the massive black hole in the center of a galaxy where indirect signals may be stronger, the density…

Astrophysics of Galaxies · Physics 2025-09-01 Zi-Chang Zhang , Hai-Chao Yuan , Yong Tang

The late universe contains a wealth of information about fundamental physics and gravity, wrapped up in non-Gaussian fields. To make use of as much information as possible it is necessary to go beyond two-point statistics. Rather than going…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-08 Alex Gough , Cora Uhlemann

Stellar and gas kinematics of galaxies are a sensitive probe of the dark matter distribution in the halo. The popular fuzzy dark matter models predict the peculiar shape of density distribution in galaxies: specific dense core with sharp…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-07 Mariia Khelashvili , Anton Rudakovskyi , Sabine Hossenfelder

I review the current status of dynamical modelling of dwarf spheroidal galaxies focusing on estimates of their dark matter content. Starting with the simplest methods using the velocity dispersion profiles I discuss the inherent issues of…

Astrophysics of Galaxies · Physics 2020-05-20 Ewa L. Lokas

In this paper, we consider the Universe deep inside of the cell of uniformity. At these scales, the Universe is filled with inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies), which disturb the…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-25 Maxim Eingorn , Alexander Zhuk

The standard model of cosmology is based on the hypothesis that the Universe is spatially homogeneous and isotropic. When interpreting most observations, this cosmological principle is applied stricto sensu: the light emitted by distant…

General Relativity and Quantum Cosmology · Physics 2024-01-15 Pierre Fleury

We perform a study both statistical and theoretical for cosmological models of matter creation and their ability to describe effective phantom models of dark energy. Such models are beyond the $\Lambda$CDM model since the resulting cosmic…

General Relativity and Quantum Cosmology · Physics 2020-04-23 Víctor H. Cárdenas , Miguel Cruz , Samuel Lepe , Shin'ichi Nojiri , Sergei D. Odintsov

According to the cosmological model without singularity, there are s-matter and v-matter which are symmetric and have oppose gravitational masses. In V-breaking s-matter is similar to dark energy to cause expansion of the universe with an…

General Physics · Physics 2010-01-26 Shi-Hao Chen

We develop an analytic halo model for the distribution of dust around galaxies. The model results are compared with the observed surface dust density profile measured through reddening of background quasars in the Sloan Digital Sky Survey…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Shogo Masaki , Naoki Yoshida

We discuss the diffusion phenomenon in the parabolic and hyperbolic regimes. New effects related to the finite velocity of the diffusion process are predicted, that can partially explain the strange behavior associated to adsorption…

Mathematical Physics · Physics 2014-02-13 A. Sapora , M. Codegone , G. Barbero

Recent observations have uncovered a remarkably flat and extremely diffuse stellar distribution within the almost dark dwarf galaxy Nube, posing a challenge to the standard cold dark matter scenario. In this study, we employ numerical…

Astrophysics of Galaxies · Physics 2025-03-07 Yu-Ming Yang , Zhao-Chen Zhang , Xiao-Jun Bi , Peng-Fei Yin

We demonstrate the existence of distribution functions that can be used to represent spherical massless cored stellar systems embedded in cuspy dark matter halos with constant mildly tangential velocity anisotropy. In particular, we derive…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Maarten A. Breddels , Amina Helmi

The motion of a particle is studied in a random space-time. It is assumed that the velocity is small enough for the non-relativistic approximation to be valid. The randomness of the metric induces a diffusion in coordinate space. Hence it…

Quantum Physics · Physics 2009-11-11 Emilio Santos

The root-mean-square of non-relativistic warm dark matter particle velocities scales as $v_{h\textrm{rms}}(a) = v_{h\textrm{rms}}(1)/a$, where $a$ is the expansion parameter of the universe. This velocity dispersion results in a cut-off of…

General Physics · Physics 2022-09-08 Bruce Hoeneisen

In this paper, we propose a modified scale factor (MSF) that allows us to explore the accelerating expansion of the universe without invoking the traditional dark-energy model, as described in the Lambda cold dark matter ($\Lambda$CDM)…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-10 Goratamang Gaedie , Shambel Sahlu , Amare Abebe

We discuss various space-time metrics which are compatible with Einstein's equations and a previously suggested cosmology with a finite total mass. In this alternative cosmology the matter density was postulated to be a spatial delta…

General Relativity and Quantum Cosmology · Physics 2015-05-20 L. Clavelli , Gary R. Goldstein

The large-scale statistics of observables such as the galaxy density are chiefly determined by their dependence on the local coarse-grained matter density. This dependence can be measured directly and efficiently in N-body simulations by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Christian Wagner , Fabian Schmidt , Chi-Ting Chiang , Eiichiro Komatsu

Given the dimensions (including thickness) and rotation speeds for an axisymmetric galaxy, a closed-loop iterative method is designed to find the total mass, density, and surface-mass density (SMD)distributions. There is no need for…

Astrophysics · Physics 2016-08-30 Kenneth F. Nicholson

Understanding the origins and distribution of matter in the Universe is one of the most important quests in physics and astronomy. Themes range from astro-particle physics to chemical evolution in the Galaxy to cosmic nucleosynthesis and…

The distribution of the non-luminous matter in galaxies of different luminosity and Hubble type is much more than a proof of the existence of dark particles governing the structures of the Universe. Here, we will review the complex but…

Astrophysics of Galaxies · Physics 2019-02-25 Paolo Salucci