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The observation of flat rotation curves in asymptotic region of galaxies implies that the dark matter density profile decreases exponentially with the gravitational potential in this region. It is curious that this behavior is identical to…

Astrophysics of Galaxies · Physics 2014-05-06 Sanjoy K. Sarker , Allen Stern

The gravitational metric tensor implies a variable dielectric tensor of vacuum around gravitational matter. The curved spacetime in general relativity is then associated with a polarizable vacuum. It is found that the number density of the…

General Physics · Physics 2009-03-24 Xing-Hao Ye

The evidence of the phenomenon for which, in galaxies, the gravitating mass is distributed differently than the luminous mass, increases as new data become available. Furthermore, this discrepancy is well structured and it depends on the…

Astrophysics of Galaxies · Physics 2019-03-11 Paolo Salucci

According to high resolution cold dark matter (CDM) simulations, large virialized halos are formed through the constant merging of smaller halos formed at earlier times. In particular, the halo of our Galaxy may have hundreds of dark matter…

Astrophysics · Physics 2009-11-07 R. Aloisio , P. Blasi , A. V. Olinto

This work continues the construction of a recently proposed model of dark matter stars. In this model, dark matter quanta are sterile massless particles that are emitted from the central regions of the galaxy in the radial direction. As a…

General Physics · Physics 2022-01-21 Igor Nikitin

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 motion of massive test particles in dark matter is studied. It is shown that if the energy density of the dark matter making up a galactic halo has a large $r$ behavior of $1/r^2$, then contrary to intuition the motion of these test…

High Energy Physics - Phenomenology · Physics 2008-02-03 Achilles D. Speliotopoulos

Galaxies and their dark-matter halos are commonly presupposed to spin. But it is an open question how this spin manifests in halos and soliton cores made of scalar dark matter (SDM, including fuzzy/wave/ultralight-axion dark matter). One…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-14 Noah Glennon , Anthony E. Mirasola , Nathan Musoke , Mark C. Neyrinck , Chanda Prescod-Weinstein

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 estimate expression for velocity as a function of the radial coordinate $r$ by using polynomial interpolation based on the experimental data of rotational velocities at distant outer regions of galaxies. The interpolation technique has…

General Relativity and Quantum Cosmology · Physics 2016-09-02 Farook Rahaman , G. C. Shit , Banashree Sen , Saibal Ray

The polar ring galaxies (PRGs) represent an interesting type of peculiar systems in which the outer matter is rotating in the plane which is roughly perpendicular to the disk of the main galaxy. Despite the long lasting study of the PRGs…

Astrophysics of Galaxies · Physics 2018-03-14 A. Moiseev , S. Khoperskov , A. Khoperskov , K. Smirnova , A. Smirnova , A. Saburova , V. Reshetnikov

The occurrence of chaos for test particles moving around a slowly rotating black hole with a dipolar halo is studied using Poincar\'e sections. We find a novel effect, particles with angular momentum opposite to the black hole rotation have…

General Relativity and Quantum Cosmology · Physics 2014-11-17 P. S. Letelier , W. M. Vieira

Quantum effects in the era of reheating of the universe after inflation are considered. A semiclassical approach to gravity theory is applied within Starobinsky's inflationary model with backreaction. Some subtleties associated with…

General Relativity and Quantum Cosmology · Physics 2025-12-29 A. B. Arbuzov , A. A. Nikitenko

A halo is an intrinsically quantum object defined as a bound state of a spatial size which extends deeply into the classically forbidden region. Previously, halos have been observed in bound states of two and less frequently of three atoms.…

Quantum Gases · Physics 2023-04-26 G. Guijarro , G. E. Astrakharchik , J. Boronat

We consider the steady-state regime describing the density profile of a dark matter halo, if dark matter is treated as a Bose-Einstein condensate. We first solve the fluid equation for "canonical" cold dark matter, obtaining a class of…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-10 Luca Visinelli

We investigate a simple model for a galactic halo under the assumption that it is dominated by a dark matter component in the form of a Bose-Einstein condensate involving an ultra-light scalar particle. In particular we discuss the…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-16 Mark N Brook , Peter Coles

We model gravitational collapse leading to star formation in a wide range of isolated disk galaxies using a three-dimensional, smoothed particle hydrodynamics code. The model galaxies include a dark matter halo and a disk of stars and…

Astrophysics · Physics 2009-11-10 Yuexing Li , Mordecai-Mark Mac Low , Ralf S. Klessen

Discussed in the study are gravitational noise and the nature of entanglement states. Their role in forming of entangled states. Nonlocal nature of entangled states can be brought about by Polarization Variables. Polarization Variables…

Quantum Physics · Physics 2007-05-23 T. F. Kamalov

The distribution of dark matter around galactic or cluster halos has usually been assumed to be approximately isothermal with a non-zero core radius, which is expected to be of the order of the size of the visible matter distribution.…

Astrophysics · Physics 2009-10-22 Ricardo A. Flores , Joel R. Primack

Within the mirror dark matter model and dissipative dark matter models in general, halos around galaxies with active star formation (including spirals and gas rich dwarfs) are dynamical: they expand and contract in response to heating and…

Astrophysics of Galaxies · Physics 2018-05-23 R. Foot
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