scholarly journals Modified dark matter: Relating dark energy, dark matter and baryonic matter

2018 ◽  
Vol 27 (02) ◽  
pp. 1830001 ◽  
Author(s):  
Douglas Edmonds ◽  
Duncan Farrah ◽  
Djordje Minic ◽  
Y. Jack Ng ◽  
Tatsu Takeuchi
Keyword(s):  
Dark Matter ◽  
Accelerating Universe ◽  
Baryonic Matter ◽  
Positive Cosmological Constant ◽  
Critical Acceleration ◽  
Quantitative Studies ◽  
Cluster Data ◽  
Matter Detection ◽  
Gravitational Thermodynamics ◽  
Galaxy Rotation Curves

Modified dark matter (MDM) is a phenomenological model of dark matter, inspired by gravitational thermodynamics. For an accelerating universe with positive cosmological constant ([Formula: see text]), such phenomenological considerations lead to the emergence of a critical acceleration parameter related to [Formula: see text]. Such a critical acceleration is an effective phenomenological manifestation of MDM, and it is found in correlations between dark matter and baryonic matter in galaxy rotation curves. The resulting MDM mass profiles, which are sensitive to [Formula: see text], are consistent with observational data at both the galactic and cluster scales. In particular, the same critical acceleration appears both in the galactic and cluster data fits based on MDM. Furthermore, using some robust qualitative arguments, MDM appears to work well on cosmological scales, even though quantitative studies are still lacking. Finally, we comment on certain nonlocal aspects of the quanta of modified dark matter, which may lead to novel nonparticle phenomenology and which may explain why, so far, dark matter detection experiments have failed to detect dark matter particles.

scholarly journals MODIFIED GRAVITY AS A COMMON CAUSE FOR COSMIC ACCELERATION AND FLAT GALAXY ROTATION CURVES

2012 ◽  
Vol 21 (11) ◽  
pp. 1242002 ◽  
Author(s):  
PRITI MISHRA ◽  
TEJINDER P. SINGH
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmic Acceleration ◽  
Accelerating Universe ◽  
Rotation Curves ◽  
Common Cause ◽  
Order Of Magnitude ◽  
Flat Rotation Curves ◽  
Acceleration Of The Universe ◽  
Galaxy Rotation Curves

Flat galaxy rotation curves and the accelerating Universe both imply the existence of a critical acceleration, which is of the same order of magnitude in both the cases, in spite of the galactic and cosmic length scales being vastly different. Yet, it is customary to explain galactic acceleration by invoking gravitationally bound dark matter, and cosmic acceleration by invoking a "repulsive" dark energy. Instead, might it not be the case that the flatness of rotation curves and the acceleration of the Universe have a common cause? In this essay we propose a modified theory of gravity. By applying the theory on galactic scales we demonstrate flat rotation curves without dark matter, and by applying it on cosmological scales we demonstrate cosmic acceleration without dark energy.

scholarly journals Modified Newtonian Dynamics: A Falsification of Cold Dark Matter

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
R. H. Sanders
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Spiral Galaxies ◽  
Elliptical Galaxies ◽  
Additional Parameter ◽  
Baryonic Matter ◽  
Critical Acceleration ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
Astronomical Object

The only viable alternative to dark matter is one in which Newtonian dynamics or gravity breaks down in the limit of low accelerations, as in modified Newtonian dynamics (MONDs). This hypothesis, suggested by Milgrom, has been successful in explaining systematic properties of spiral and elliptical galaxies and predicting in detail the observed rotation curves of spiral galaxies with only one additional parameter—a critical acceleration which is on the order of the cosmologically interesting value of . MOND may be viewed as an algorithm for calculating the distribution of force in an astronomical object from the observed distribution of baryonic matter. The fact that it works very well on the scale of galaxies is problematic for cold dark matter (CDM). Here I present evidence in favor of this assertion and claim that this is, in effect, a falsification of CDM on the scale of galaxies.

scholarly journals Prediction of tunable spin-orbit gapped materials for dark matter detection

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Katherine Inzani ◽  
Alireza Faghaninia ◽  
Sinéad M. Griffin
Keyword(s):  
Dark Matter ◽  
Spin Orbit ◽  
Dark Matter Detection ◽  
Matter Detection

scholarly journals Understanding the large inferred Einstein radii of observed low-mass galaxy clusters

2020 ◽  
Vol 494 (4) ◽  
pp. 4706-4712 ◽  
Author(s):  
Andrew Robertson ◽  
Richard Massey ◽  
Vincent Eke
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
Baryonic Matter ◽  
Analysis Method ◽  
Critical Curves ◽  
Hydrodynamical Simulation ◽  
Low Mass ◽  
Main Effects

ABSTRACT We assess a claim that observed galaxy clusters with mass ${\sim}10^{14} \mathrm{\, M_\odot }$ are more centrally concentrated than predicted in lambda cold dark matter (ΛCDM). We generate mock strong gravitational lensing observations, taking the lenses from a cosmological hydrodynamical simulation, and analyse them in the same way as the real Universe. The observed and simulated lensing arcs are consistent with one another, with three main effects responsible for the previously claimed inconsistency. First, galaxy clusters containing baryonic matter have higher central densities than their counterparts simulated with only dark matter. Secondly, a sample of clusters selected because of the presence of pronounced gravitational lensing arcs preferentially finds centrally concentrated clusters with large Einstein radii. Thirdly, lensed arcs are usually straighter than critical curves, and the chosen image analysis method (fitting circles through the arcs) overestimates the Einstein radii. After accounting for these three effects, ΛCDM predicts that galaxy clusters should produce giant lensing arcs that match those in the observed Universe.

Alpha Magnetic Spectrometer (AMS) Releases New Results on Dark Matter Detection

2015 ◽  
Vol 04 (01) ◽  
pp. 28-30
Author(s):  
Yuan-Hann Chang
Keyword(s):  
Dark Matter ◽  
Direct Detection ◽  
Magnetic Spectrometer ◽  
Gravitational Effects ◽  
Dark Matter Detection ◽  
The Universe ◽  
Matter Detection ◽  
Alpha Magnetic Spectrometer

It is known that the majority (about 80%) of the matter in the universe is not visible, but rather a hypothetical "Dark Matter". The existence of Dark Matter has been postulated to explain the discrepancies between the estimated mass of visible matters in the galaxies, and their gravitational effects. Although it has been postulated for over 70 years, and has been commonly accepted by most scientists, the essence of the Dark Matter has not yet been understood. In particular, we still do not know what constitutes the Dark Matter. Direct detection of the Dark Matter is therefore one of the most important issues in physics.

scholarly journals Galactic halo models and particle dark-matter detection

1998 ◽  
Vol 57 (6) ◽  
pp. 3256-3263 ◽  
Author(s):  
Marc Kamionkowski ◽  
Ali Kinkhabwala
Keyword(s):  
Dark Matter ◽  
Galactic Halo ◽  
Particle Dark Matter ◽  
Dark Matter Detection ◽  
Matter Detection
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