scholarly journals Implications of baryon–dark matter interaction on IGM temperature and tSZ effect with magnetic field

2020 ◽  
Vol 500 (1) ◽  
pp. 643-654
Author(s):  
Arun Kumar Pandey ◽  
Sunil Malik ◽  
T R Seshadri
Keyword(s):  
Magnetic Field ◽  
Dark Matter ◽  
Interaction Cross Section ◽  
Ionization State ◽  
Microwave Background ◽  
Magnetic Turbulence ◽  
Matter Interaction ◽  
Ionization Fraction ◽  
The Universe ◽  
The Magnetic Field

ABSTRACT We show that the combined effect of cosmic magnetic field and a possible non-standard interaction between baryons and dark matter (DM) has interesting consequences on the thermal Sunyaev−Zel’dovich (tSZ) effect depending on the temperature and the ionization state of the intergalactic medium. The drag force between the baryons and DM due to the relative velocity between them, and their temperature difference results in heat transfer between these two species. At the same time, the ambipolar diffusion and the decaying magnetic turbulence tends to heat up the baryons. This interplay of these two processes give rise to different evolution histories of the thermal and ionization state of the universe and hence influences the cosmic microwave background (CMB) spectrum at small scales through the tSZ effect. In this work, we have computed the evolution of the temperature, ionization fraction, and the y-parameter of the CMB for different strengths of the magnetic field and the interaction cross-section. We note that the y-parameter can be significantly enhanced with the inclusion of magnetic field and baryon–DM interaction as compared to the case when these are absent. The enhancement depends on the strength of the magnetic field.

scholarly journals Can accelerated expansion of the universe be due to spacetime vorticity?

2018 ◽  
Vol 33 (40) ◽  
pp. 1850240
Author(s):  
Babur M. Mirza
Keyword(s):  
Magnetic Field ◽  
Accelerated Expansion ◽  
Newtonian Gravity ◽  
Hubble’S Parameter ◽  
Cosmic Expansion ◽  
Zero Curvature ◽  
Expansion Of The Universe ◽  
General Relativistic ◽  
The Universe ◽  
The Magnetic Field

We present here a general relativistic mechanism for accelerated cosmic expansion and the Hubble’s parameter. It is shown that spacetime vorticity coupled to the magnetic field density in galaxies causes the galaxies to recede from one another at a rate equal to the Hubble’s constant. We therefore predict an oscillatory universe, with zero curvature, without assuming violation of Newtonian gravity at large distances or invoking dark energy/dark matter hypotheses. The value of the Hubble’s constant, along with the scale of expansion, as well as the high isotropy of CMB radiation are deduced from the model.

scholarly journals Dark matter annihilation in the universe

2014 ◽  
Vol 30 ◽  
pp. 1460256 ◽  
Author(s):  
Pierre Salati
Keyword(s):  
Dark Matter ◽  
Galactic Halo ◽  
Light Element ◽  
Big Bang ◽  
Microwave Background ◽  
Dark Matter Annihilation ◽  
Element Abundances ◽  
Primordial Plasma ◽  
Relic Abundance ◽  
The Universe

The astronomical dark matter is an essential component of the Universe and yet its nature is still unresolved. It could be made of neutral and massive elementary particles which are their own antimatter partners. These dark matter species undergo mutual annihilations whose effects are briefly reviewed in this article. Dark matter annihilation plays a key role at early times as it sets the relic abundance of the particles once they have decoupled from the primordial plasma. A weak annihilation cross section naturally leads to a cosmological abundance in agreement with observations. Dark matter species subsequently annihilate — or decay — during Big Bang nucleosynthesis and could play havoc with the light element abundances unless they offer a possible solution to the 7 Li problem. They could also reionize the intergalactic medium after recombination and leave visible imprints in the cosmic microwave background. But one of the most exciting aspects of the question lies in the possibility to indirectly detect the dark matter species through the rare antimatter particles — antiprotons, positrons and antideuterons — which they produce as they currently annihilate inside the galactic halo. Finally, the effects of dark matter annihilation on stars is discussed.

scholarly journals Local Bubble contribution to the 353-GHz dust polarized emission

2019 ◽  
Vol 631 ◽  
pp. L11 ◽  
Author(s):  
R. Skalidis ◽  
V. Pelgrims
Keyword(s):  
Magnetic Field ◽  
Line Of Sight ◽  
Optical Polarization ◽  
Local Interstellar Medium ◽  
Microwave Background ◽  
Local Bubble ◽  
Submillimeter Wavelengths ◽  
Polarized Emission ◽  
The Magnetic Field ◽  
Robust Evidence

It has not been shown so far whether the diffuse Galactic polarized emission at frequencies relevant for cosmic microwave background (CMB) studies originates from nearby or more distant regions of our Galaxy. This questions previous attempts that have been made to constrain magnetic field models at local and large scales. The scope of this work is to investigate and quantify the contribution of the dusty and magnetized local interstellar medium to the observed emission that is polarized by thermal dust. We used stars as distance candles and probed the line-of-sight submillimeter polarization properties by comparing the emission that is polarized by thermal dust at submillimeter wavelengths and the optical polarization caused by starlight. We provide statistically robust evidence that at high Galactic latitudes (|b| ≥ 60°), the 353 GHz polarized sky as observed by Planck is dominated by a close-by magnetized structure that extends between 200 and 300 pc and coincides with the shell of the Local Bubble. Our result will assist modeling the magnetic field of the Local Bubble and characterizing the CMB Galactic foregrounds.

scholarly journals Large-Scale Structure of the Universe in Unstable Dark Matter Models

1988 ◽  
Vol 130 ◽  
pp. 293-300
Author(s):  
A.G. Doroshkevich ◽  
A.A. Klypin ◽  
M.U. Khlopov
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Large Scale ◽  
Numerical Models ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Microwave Background ◽  
Physical Background ◽  
The Mean ◽  
The Universe

Processes of the formation and the evolution of the large-scale structure are discussed in the framework of unstable dark matter models. Six numerical models are presented. The projected distribution of simulated galaxies on the sky, wedge diagrams, correlation functions and the mean linear scale of voids are presented. Physical background of the hypothesis of unstable particles and possible observational tests are discussed. The level of the microwave background fluctuations is estimated analytically. Special attention is given to late stage of supercluster evolution and galaxy formation.

scholarly journals Photons in a cold axion background and strong magnetic fields: Polarimetric consequences

2015 ◽  
Vol 30 (17) ◽  
pp. 1550099 ◽  
Author(s):  
Domènec Espriu ◽  
Albert Renau
Keyword(s):  
Magnetic Field ◽  
Dark Matter ◽  
Galactic Halo ◽  
Local Density ◽  
Polarization Plane ◽  
Strong Magnetic Fields ◽  
Two Photon ◽  
Main Effect ◽  
Optical Table ◽  
The Magnetic Field

In this work, we analyze the propagation of photons in an environment where a strong magnetic field (perpendicular to the photon momenta) coexists with an oscillating cold axion background with the characteristics expected from dark matter in the galactic halo. Qualitatively, the main effect of the combined background is to produce a three-way mixing among the two photon polarizations and the axion. It is interesting to note that in spite of the extremely weak interaction of photons with the cold axion background, its effects compete with those coming from the magnetic field in some regions of the parameter space. We determine (with one plausible simplification) the proper frequencies and eigenvectors as well as the corresponding photon ellipticity and induced rotation of the polarization plane that depend both on the magnetic field and the local density of axions. We also comment on the possibility that some of the predicted effects could be measured in optical table-top experiments.

NEW LIMITS ON THE WIMP COLD DARK MATTER INTERACTION CROSS SECTION FROM THE UK EXPERIMENT

COSMO-97 ◽  
1998 ◽  
Author(s):  
T. Ali ◽  
T. J. Sumner ◽  
J. J. Quenby ◽  
A. Bewick ◽  
N. J. T. Smith ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Cold Dark Matter ◽  
Interaction Cross Section ◽  
Matter Interaction ◽  
The Uk

scholarly journals Particle Production via Dirac Dipole Moments in the Magnetized and Nonmagnetized Exponentially Expanding Universe

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Semra Gurtas Dogan ◽  
Ganim Gecim ◽  
Yusuf Sucu
Keyword(s):  
Magnetic Field ◽  
Decomposition Method ◽  
Particle Production ◽  
Dipole Moments ◽  
Dirac Particle ◽  
Future Time ◽  
Magnetization Density ◽  
Total Polarization ◽  
The Universe ◽  
The Magnetic Field

In the present paper, we solve the Dirac equation in the 2+1 dimensional exponentially expanding magnetized by uniform magnetic field and nonmagnetized universes, separately. Asymptotic behaviors of the solutions are determined. Using these results we discuss the current of a Dirac particle to discuss the polarization densities and the magnetization density in the context of Gordon decomposition method. In this work we also calculate the total polarization and magnetization, to investigate how the magnetic field affects the particle production. Furthermore, the electric and the magnetic dipole moments are calculated, and based on these, we have discussed the effects of the dipole moments on the charge distribution of the universe and its conductivity for both the early and the future time epoch in the presence/absence of a constant magnetic field and exponentially expanding spacetime.

scholarly journals General relativistic magnetic perturbations and dynamo effects in extragalactic radiosources

2010 ◽  
Vol 6 (S274) ◽  
pp. 393-397
Author(s):  
L. C. Garcia de Andrade
Keyword(s):  
Magnetic Field ◽  
Magnetic Energy ◽  
Magnetic Fluctuations ◽  
Dynamo Action ◽  
Magnetic Contrast ◽  
Mhd Dynamo ◽  
Curvature Energy ◽  
Induction Equation ◽  
The Universe ◽  
The Magnetic Field

AbstractBy making use of the MHD self-induction equation in general relativity (GR), recently derived by Clarkson and Marklund (2005), it is shown that when Friedmann universe possesses a spatial section whose Riemannian curvature is negative, the magnetic energy bounds computed by Nuñez (2002) also bounds the growth rate of the magnetic field given by the strain matrix of dynamo flow. Since in GR-MHD dynamo equation, the Ricci tensor couples with the universe magnetic field, only through diffusion, and most ages are highly conductive the interest is more theoretical here, and only very specific plasma astrophysical problems can be address such as in laboratory plasmas. Magnetic fields and the negative curvature of some isotropic cosmologies, contribute to enhence the amplification of the magnetic field. Ricci curvature energy is shown to add to strain matrix of the flow, to enhance dynamo action in the universe. Magnetic fluctuations of the Clarkson-Marklund equations for a constant magnetic field seed in highly conductive flat universes, leads to a magnetic contrast of ≈ 2, which is well within observational limits from extragalactic radiosources of ≈ 1.7. In the magnetic helicity fluctuations the magnetic contrast shows that the dynamo effects can be driven by these fluctuations.

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