scholarly journals Revisiting the constraints on annihilating dark matter by the radio observational data of M31

2016 ◽  
Vol 94 (2) ◽  
Author(s):  
Man Ho Chan
Keyword(s):  
Dark Matter ◽  
Observational Data

Nonlocal Gravity and Dark Matter

2017 ◽  
Author(s):  
Bahram Mashhoon
Keyword(s):  
Dark Matter ◽  
Solar System ◽  
Observational Data ◽  
Virial Theorem ◽  
Spiral Galaxies ◽  
Clusters Of Galaxies ◽  
The Galaxy

The implications of linearized NLG for the gravitational physics of the Solar System, spiral galaxies and nearby clusters of galaxies are critically examined in this chapter. In the Newtonian regime, NLG involves a reciprocal kernel with three length parameters. We discuss the determination of these parameters by comparing the predictions of the theory with observational data. Furthermore, the virial theorem for the Newtonian regime of NLG is derived and its consequences for nearby “isolated” astronomical systems in virial equilibrium are investigated. For such a galaxy, in particular, the galaxy’s baryonic diameter namely, the diameter of the smallest sphere that completely surrounds the baryonic system at the present time, is predicted to be larger than the basic nonlocality lengthscale, which is about 3 kpc, times the effective dark matter fraction of the galaxy.

P-STARS

2004 ◽  
Vol 13 (09) ◽  
pp. 1917-1926 ◽  
Author(s):  
PAOLO CEA
Keyword(s):  
Dark Matter ◽  
Neutron Stars ◽  
Observational Data ◽  
Gravitational Collapse ◽  
Cold Dark Matter ◽  
Compact Stars ◽  
Cooling Curves ◽  
New Class

P-Stars are a new class of compact stars made of up and down quarks in β-equilibrium with electrons in an Abelian chromomagnetic condensate. We show that P-Stars are able to account for compact stars with R≲6 Km , as well as stars with radius comparable with canonical Neutron Stars. We find that cooling curves of P-Stars compare rather well with observational data. We suggest that P-Matter produced at the primordial deconfinement transition is a viable candidate for baryonic Cold Dark Matter. Finally, we show that P-Stars are able to overcome the gravitational collapse even for masses much greater than 106 M⊙.

scholarly journals Statefinder and Om Diagnostics for New Generalized Chaplygin Gas Model

Universe ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 362
Author(s):  
Abdulla Al Mamon ◽  
Vipin Chandra Dubey ◽  
Kazuharu Bamba
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Observational Data ◽  
Hubble Parameter ◽  
Chaplygin Gas ◽  
Distance Modulus ◽  
Generalized Chaplygin Gas ◽  
New Model ◽  
Λcdm Model ◽  
Data Points

We explore a unified model of dark matter and dark energy. This new model is a generalization of the generalized Chaplygin gas model and is known as a new generalized Chaplygin gas (NGCG) model. We study the evolutions of the Hubble parameter and the distance modulus for the model under consideration and the standard ΛCDM model and compare that with the observational datasets. Furthermore, we demonstrate two geometric diagnostics analyses including the statefinder (r,s) and Om(z) to the discriminant NGCG model from the standard ΛCDM model. The trajectories of evolution for (r,s) and Om(z) diagnostic planes are shown to understand the geometrical behavior of the NGCG model by using different observational data points.

scholarly journals New cosmographic constraints on the dark energy and dark matter coupling

2016 ◽  
Vol 25 (05) ◽  
pp. 1650056 ◽  
Author(s):  
Yu. L. Bolotin ◽  
V. A. Cherkaskiy ◽  
O. A. Lemets
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Observational Data ◽  
Coupling Constant ◽  
Dark Sector ◽  
Suggested Approach ◽  
Matter Coupling ◽  
Novel Approach

We propose a novel approach to obtain limitations on the dark energy (DE) and dark matter (DM) coupling. The suggested approach allows us to express the coupling constant in terms of the cosmographic parameters (CPs). It enables us to find constraints on the coupling constant directly based on observational data and to restrict number of numerous models describing interaction in the dark sector.

scholarly journals UPPER LIMITS ON DENSITY OF DARK MATTER IN SOLAR SYSTEM

2006 ◽  
Vol 15 (04) ◽  
pp. 615-618 ◽  
Author(s):  
I. B. KHRIPLOVICH ◽  
E. V. PITJEVA
Keyword(s):  
Dark Matter ◽  
Solar System ◽  
Observational Data ◽  
Perihelion Precession ◽  
Upper Limits

The analysis of the observational data for the secular perihelion precession of Mercury, Earth, and Mars, based on the EPM2004 ephemerides, results in new upper limits on density of dark matter in the solar system.

scholarly journals Structure and Kinematics of Polar Ring Galaxies: New Observations and Estimation of the Dark Halo Shape

2015 ◽  
Vol 24 (1) ◽  
Author(s):  
A. Moiseev ◽  
S. Khoperskov ◽  
A. Khoperskov ◽  
K. Smirnova ◽  
A. Smirnova ◽  
...  
Keyword(s):  
Dark Matter ◽  
Observational Data ◽  
Dark Matter Halo ◽  
Dark Halo ◽  
Dark Matter Halos ◽  
Ionized Gas ◽  
Polar Ring ◽  
Gas Kinematics ◽  
Open Questions ◽  
Ring Galaxies

AbstractThe 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, the amount of observational data detailed enough is insufficient; there still remain many open questions. Among the most interesting issues, there are: estimating the flattening of dark matter halos in these systems and verifying the assumption that the most massive polar structures were formed by accretion of the matter from intergalactic filaments. The new catalog recently compiled by our team using SDSS images increased, by several times, the number of known PRGs. The current paper gives an overview of our latest results on the study of morphological and photometric structure of the PRGs. Using the stellar and ionized gas kinematics data based on spectroscopic observations with the Russian 6-m telescope, we estimate the shape of dark matter halo in individual galaxies.

scholarly journals Parameters of the Dark Halo distribution around M 31

2000 ◽  
Vol 174 ◽  
pp. 381-384
Author(s):  
P. Tenjes ◽  
J. Einasto
Keyword(s):  
Dark Matter ◽  
Observational Data ◽  
Dark Halo ◽  
Visible Matter ◽  
M 31

AbstractAvailable observational data allow us to discriminate between the visible matter and the dark matter in M 31 and thus to determine the most important parameters of the dark halo (the mass, the radius and the outer extent).

scholarly journals Massive primordial black holes in contemporary and young universe (old predictions and new data)

2018 ◽  
Vol 33 (31) ◽  
pp. 1844029 ◽  
Author(s):  
A. D. Dolgov
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Observational Data ◽  
High Population ◽  
Primordial Black Holes ◽  
Astronomical Data ◽  
The Universe

A brief review of the recent astronomical data, indicating that the universe is abundantly populated by heavy black holes (BH), is presented. Conventional astrophysics and cosmology cannot explain such a high population of BHs. A mechanism of the paper of 1963 is described, which at least qualitatively explained the observational data. In particular, the prediction that massive primordial BHs can be cosmological dark matter “particles” is discussed.

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