scholarly journals Determination of “inos” Masses Composing Galactic Halos

1987 ◽  
Vol 124 ◽  
pp. 723-726
Author(s):  
D. J. Song ◽  
R. Ruffini
Keyword(s):  
Dark Matter ◽  
Physical Properties ◽  
Galactic Halos ◽  
Modern Cosmology ◽  
The Universe

One of the most important discoveries in modern cosmology and astrophysics is that the dark matter dominates at every scale of the Universe (Rubin et al., 1978, Forman et al., 1985, Faber and Gallagher, 1979, Sancisi, 1987). The problem that follows is to understand the components of the dark matter and to determine the physical properties of these components.

A Tale of Two Infinities

2021 ◽  
Author(s):  
Gianfranco Bertone
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Direct Detection ◽  
Traditional Approach ◽  
Fundamental Physics ◽  
Modern Cosmology ◽  
Nobel Prize In Physics ◽  
The Universe ◽  
Modern Astronomy

The spectacular advances of modern astronomy have opened our horizon on an unexpected cosmos: a dark, mysterious Universe, populated by enigmatic entities we know very little about, like black holes, or nothing at all, like dark matter and dark energy. In this book, I discuss how the rise of a new discipline dubbed multimessenger astronomy is bringing about a revolution in our understanding of the cosmos, by combining the traditional approach based on the observation of light from celestial objects, with a new one based on other ‘messengers’—such as gravitational waves, neutrinos, and cosmic rays—that carry information from otherwise inaccessible corners of the Universe. Much has been written about the extraordinary potential of this new discipline, since the 2017 Nobel Prize in physics was awarded for the direct detection of gravitational waves. But here I will take a different angle and explore how gravitational waves and other messengers might help us break the stalemate that has been plaguing fundamental physics for four decades, and to consolidate the foundations of modern cosmology.

scholarly journals N-body Simulations of Galaxy Formation

1988 ◽  
Vol 130 ◽  
pp. 259-271
Author(s):  
Carlos S. Frenk
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Large Scale Structure ◽  
High Density ◽  
Galactic Halos ◽  
Body Techniques ◽  
Massive Halos ◽  
The Universe

Modern N-body techniques allow the study of galaxy formation in the wider context of the formation of large-scale structure in the Universe. The results of such a study within the cold dark matter cosmogony are described. Dark galactic halos form at relatively recent epochs. Their properties and abundance are similar to those inferred for the halos of real galaxies. Massive halos tend to form preferentially in high density regions and as a result the galaxies that form within them are significantly more clustered than the underlying mass. This natural bias may be strong enough to reconcile the observed clustering of galaxies with the assumption that Ω = 1.

Dark Matter

2021 ◽  
pp. 66-78
Author(s):  
Gianfranco Bertone
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Waves ◽  
Expansion Rate ◽  
The Earth ◽  
Modern Cosmology ◽  
Large Effort ◽  
The Universe

I introduce here the problem of dark energy, a substance that appears to be pushing the Universe to expand ever faster and discuss the large effort currently in place to understand its origin. I describe the surprising recent discovery of a widening crack in the cathedral of modern cosmology arising from the measurement of the expansion rate of the Universe. And I argue that gravitational waves observations can help us to either repair that crack, or to bring down that magnificent building, in case it turns out to be fatally flawed. Before all women and all men. Before animals, plants, archaeans, bacteria. Before the Earth was formed and the stars were lit. Before everything we know, the Universe was immersed in an amorphous and oblivious darkness.

scholarly journals Accelerated expansion of the Universe in the presence of dark matter pressure

2020 ◽  
Vol 98 (2) ◽  
pp. 210-216
Author(s):  
Zeinab Rezaei
Keyword(s):  
Dark Matter ◽  
Equation Of State ◽  
Hubble Parameter ◽  
Energy Equation ◽  
Accelerated Expansion ◽  
Luminosity Distance ◽  
Modern Cosmology ◽  
History Of ◽  
Expansion Of The Universe ◽  
The Universe

Expansion dynamics of the Universe is an important subject in modern cosmology. The dark energy equation of state determines these dynamics so that the Universe is in an accelerating phase. However, dark matter (DM) can also affect the accelerated expansion of the Universe through its equation of state. In the present work, we explore the expansion dynamics of the Universe in the presence of DM pressure. In this regard, applying the DM equation of state from the observational data related to the rotational curves of galaxies, we calculate the evolution of DM density. Moreover, the Hubble parameter, history of scale factor, luminosity distance, and deceleration parameter are studied while the DM pressure is taken into account. Our results verify that the DM pressure leads to higher values of the Hubble parameter at each redshift and the expansion of the Universe grows due to the DM pressure.

scholarly journals Dark Matter - Are They Insulators to Electromagnetic Radiation?

2022 ◽  
Author(s):  
Sayan Bag ◽  
Arijit Bag
Keyword(s):  
Dark Matter ◽  
Electromagnetic Radiation ◽  
Present Article ◽  
Experimental Verification ◽  
Verification Method ◽  
Outstanding Problem ◽  
Normal Matter ◽  
Modern Cosmology ◽  
The Universe ◽  
Peculiar Behavior

The detection of Dark Matter is the greatest outstanding problem in modern cosmology. Several attempts have been taken for this without any remarkable success. To find out a suitable way of detection we need to understand its nature comprehensively. In the present article, a hypothesis is described considering Dark Matter as a normal matter. Its peculiar behavior is explained considering its existence in BEC state in the coolest part of the universe that makes it an electromagnetic insulator. Depending upon this hypothesis an experimental verification method is proposed.

scholarly journals A MODEL OF A SIMPLE, BARYON-DOMINATED UNIVERSE THAT EXPANDS AT AN EVER-INCREASING RATE WITHOUT RELYING ON VACUUM ENERGY (Λ)

2011 ◽  
Vol 26 (33) ◽  
pp. 2501-2521
Author(s):  
GREG P. PROPER
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Dark Energy ◽  
Vacuum Energy ◽  
Absolute Magnitude ◽  
Short Paper ◽  
Modern Cosmology ◽  
Spacetime Metric ◽  
The Universe ◽  
Prevailing View

The prevailing view in modern cosmology is that the universe is comprised of immense quantities of exotic materials (i.e. Dark Matter and Dark Energy) that have yet to be positively identified. However, there is also a small group of scientists who believe that the answer to this dilemma is to be found in the modification of gravity (i.e. General Relativity). This short paper states that if we make the bold assumption that all objects/observers are comprised of sets of spacetime coordinates that change (albeit slowly) as the universe ages, then three puzzles that currently confront cosmologists, astronomers and astrophysicists can easily be answered using relatively simple calculations. The condition necessary to explore this possibility can be obtained if one postulates that relativistic gravitational potential lessens (in absolute magnitude) everywhere as the universe ages (n). That is, the spacetime metric gμν(x)→gμν(x, n). If gravity behaves in this manner, then it can be shown that it is the causitive agent of indeterminism in nature.

DENSITY PERTURBATIONS AND THE CHAPLYGIN GAS

2009 ◽  
Vol 24 (08n09) ◽  
pp. 1674-1677
Author(s):  
SANDRO SILVA E COSTA
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Power Spectrum ◽  
Cosmological Model ◽  
Chaplygin Gas ◽  
Scale Factor ◽  
Modified Chaplygin Gas ◽  
Modern Cosmology ◽  
Density Perturbations ◽  
The Universe

One approach in modern cosmology consists in supposing that dark matter and dark energy are different manifestations of a single 'quartessential' fluid. Following such idea, this work presents a summary of some studies of the evolution of density perturbations in a flat cosmological model with a modified Chaplygin gas acting as a single component. Our goal is to obtain properties of the model which can be used to distinguish it from another cosmological models which have the same solutions for the general evolution of the scale factor of the universe, even without the construction of the power spectrum. Both our analytical and numerical results clearly indicate as one interesting feature of the model the presence of peaks in the evolution of the density constrast.

scholarly journals Dark Matter and Cooling Flows

1988 ◽  
Vol 130 ◽  
pp. 429-435
Author(s):  
B. J. Carr ◽  
K. M. Ashman
Keyword(s):  
Elementary Particle ◽  
Dark Matter ◽  
Large Fraction ◽  
Critical Density ◽  
Galactic Halos ◽  
Present Epoch ◽  
Cooling Flows ◽  
The Universe ◽  
Made In

Cosmological arguments suggest that a large fraction of the baryons in the Universe are dark. Although the background dark matter required to make up the critical density would have to consist of some kind of elementary particle, the dark matter in galactic halos could be baryonic. In particular, we argue that it could consist of jupiters made in pregalactic or protogalactic cooling flows. These would be analagous to the cluster cooling flows observed at the present epoch but on a smaller scale.

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