scholarly journals Effects of primordial magnetic fields on CMB

2014 ◽  
Vol 10 (S306) ◽  
pp. 159-161 ◽  
Author(s):  
Héctor J. Hortúa ◽  
Leonardo Castañeda
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
Magnetic Fields ◽  
Large Scale ◽  
Unsolved Problem ◽  
Microwave Background ◽  
Cosmological Perturbation ◽  
Cosmological Perturbation Theory ◽  
Primordial Magnetic Fields ◽  
Primordial Magnetic Field

AbstractThe origin of large-scale magnetic fields is an unsolved problem in cosmology. In order to overcome, a possible scenario comes from the idea that these fields emerged from a small primordial magnetic field (PMF), produced in the early universe. This field could lead to the observed large-scales magnetic fields but also, would have left an imprint on the cosmic microwave background (CMB). In this work we summarize some statistical properties of this PMFs on the FLRW background. Then, we show the resulting PMF power spectrum using cosmological perturbation theory and some effects of PMFs on the CMB anisotropies.

COSMOLOGICAL CONSTRAINT ON BRANS-DICKE THEORY

2011 ◽  
Vol 01 ◽  
pp. 195-202
Author(s):  
XUELEI CHEN ◽  
FENGQUAN WU
Keyword(s):  
Monte Carlo ◽  
Perturbation Theory ◽  
Markov Chain ◽  
Large Scale ◽  
Mcmc Method ◽  
Covariant Formalism ◽  
Microwave Background ◽  
Cosmological Perturbation ◽  
Cosmological Perturbation Theory ◽  
Cosmological Constraint

We develop the covariant formalism of the cosmological perturbation theory for the Brans-Dicke gravity, and use it to calculate the cosmic microwave background (CMB) anisotropy and large scale structure (LSS) power spectrum. We introduce a new parameter ζ which is related to the Brans-Dicke parameter ζ = ln (1/ω + 1), and use the Markov-Chain Monte Carlo (MCMC) method to explore the parameter space. Using the latest CMB data published by WMAP, ACBAR, CBI, Boomerang teams, and the LSS data from the SDSS survey DR4, we find that the the 2σ (95.5%) bound on ζ is about |ζ| > 10-2, or |ω| > 102, the precise limit depends somewhat on the prior used.

scholarly journals Tracing Primordial Magnetic Fields with 21 cm Line Observations

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 37 ◽  
Author(s):  
Kerstin Kunze
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Cosmic Microwave Background ◽  
Large Scale ◽  
Numerical Solutions ◽  
Gaussian Random Field ◽  
Microwave Background ◽  
Matter Power Spectrum ◽  
Primordial Magnetic Fields ◽  
The Universe

Magnetic fields are observed on a large range of scales in the universe. Up until recently, the evidence always pointed to magnetic fields associated with some kind of structure, from planets to clusters of galaxies. Blazar observations have been used to posit the first evidence of truly cosmological magnetic fields or void magnetic fields. A cosmological magnetic field generated in the very early universe before recombination has implications for the cosmic microwave background (CMB), large scale structure as well as the 21 cm line signal. In particular, the Lorentz term causes a change in the linear matter power spectrum. Its implication on the 21 cm line signal was the focus of our recent simulations which will be summarised here. Modelling the cosmological magnetic field as a gaussian random field numerical solutions were found for magnetic fields with present day amplitudes of 5 nG and negative spectral indices which are within the range of observational constraints imposed by the cosmic microwave background (CMB).

scholarly journals PRIMORDIAL MAGNETIC FIELDS

1998 ◽  
Vol 07 (03) ◽  
pp. 331-349 ◽  
Author(s):  
KARI ENQVIST
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Particle Physics ◽  
Large Scale ◽  
Magnetic Energy ◽  
Galactic Magnetic Fields ◽  
Microscopic Field ◽  
Primordial Magnetic Fields ◽  
Primordial Magnetic Field ◽  
The Magnetic Field

The explanation of the observed galactic magnetic fields may require the existence of a primordial magnetic field. Such a field may arise during the early cosmological phase transitions, or because of other particle physics related phenomena in the very early universe reviewed here. The turbulent evolution of the initial, randomly fluctuating microscopic field to a large-scale macroscopic field can be described in terms of a shell model, which provides an approximation to the complete magnetohydrodynamics. The results indicate that there is an inverse cascade of magnetic energy whereby the coherence of the magnetic field is increased by many orders of magnitude. Cosmological seed fields roughly of the order of 10-20 G at the scale of protogalaxy, as required by the dynamo explanation of galactic magnetic fields, thus seem plausible.

scholarly journals PRIMORDIAL MAGNETIC FIELDS BY COSMIC INFLATION

2012 ◽  
Vol 12 ◽  
pp. 264-271
Author(s):  
SHU-LIN CHENG ◽  
WO-LUNG LEE ◽  
KIN-WANG NG
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Cosmic Microwave Background ◽  
Quadrupole Moment ◽  
Microwave Background ◽  
Cosmic Inflation ◽  
Slow Roll ◽  
Primordial Magnetic Fields ◽  
Primordial Magnetic Field ◽  
Spinodal Instability

Contrary to the conventional wisdom, we find that it is plausible to generate primordial magnetic seed fields via spinodal instability efficiently during cosmic inflation provided that a fast-roll stage is involved before the inflaton entering into the slow-roll phase. Moreover, the primordial magnetic field produced in such a mechanism can be used to constrain the low quadrupole moment of Cosmic Microwave Background.

scholarly journals Primordial Magnetic Field Effects on the CMB and Large-Scale Structure

2010 ◽  
Vol 2010 ◽  
pp. 1-19 ◽  
Author(s):  
Dai G. Yamazaki ◽  
Kiyotomo Ichiki ◽  
Toshitaka Kajino ◽  
Grant J. Mathews
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Large Scale Structure ◽  
Big Bang ◽  
Scale Structure ◽  
Magnetic Field Effects ◽  
Power Spectral ◽  
Primordial Magnetic Field ◽  
The Big Bang

Magnetic fields are everywhere in nature, and they play an important role in every astronomical environment which involves the formation of plasma and currents. It is natural therefore to suppose that magnetic fields could be present in the turbulent high-temperature environment of the big bang. Such a primordial magnetic field (PMF) would be expected to manifest itself in the cosmic microwave background (CMB) temperature and polarization anisotropies, and also in the formation of large-scale structure. In this paper, we summarize the theoretical framework which we have developed to calculate the PMF power spectrum to high precision. Using this formulation, we summarize calculations of the effects of a PMF which take accurate quantitative account of the time evolution of the cutoff scale. We review the constructed numerical program, which is without approximation, and an improvement over the approach used in a number of previous works for studying the effect of the PMF on the cosmological perturbations. We demonstrate how the PMF is an important cosmological physical process on small scales. We also summarize the current constraints on the PMF amplitudeBλand the power spectral indexnBwhich have been deduced from the available CMB observational data by using our computational framework.

EFFECTS OF PRIMORDIAL MAGNETIC FIELD ON EARLY UNIVERSE

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1695-1706 ◽  
Author(s):  
DAI G. YAMAZAKI ◽  
KIYOTOMO ICHIKI ◽  
KAJINO TOSHITAKA ◽  
GRANT J. MATHEWS
Keyword(s):  
Magnetic Field ◽  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
Early Universe ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Microwave Background ◽  
Primordial Magnetic Field

The existence of a primordial magnetic field (PMF) would affect both the temperature and polarization anisotropies of the cosmic microwave background (CMB) and the formation of the large scale structure(LSS). It also provides a plausible explanation for the disparity between observations and theoretical fits to the CMB power spectrum and the LSS. Here we report on calculations of not only the numerical power spectrum of the PMF, but also the correlations between the PMF power spectrum and the primary curvature perturbations.

scholarly journals PROBING FOR DYNAMICS OF DARK-ENERGY IN MASS VARYING NEUTRINOS: COSMIC MICROWAVE BACKGROUND RADIATION AND LARGE SCALE STRUCTURE

2007 ◽  
Vol 22 (25n28) ◽  
pp. 2131-2142 ◽  
Author(s):  
YONG-YEON KEUM
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Cosmic Microwave Background ◽  
Large Scale ◽  
Background Radiation ◽  
Coupling Parameter ◽  
Cosmic Acceleration ◽  
Microwave Background ◽  
Cosmological Perturbation ◽  
Cosmological Perturbation Theory

We present cosmological perturbation theory in neutrino probe interacting dark-energy models, and calculate cosmic microwave background anisotropies and matter power spectrum. In these models, the evolution of the mass of neutrinos is determined by the quintessence scalar field, which is responsible for the cosmic acceleration today. We consider several types of scalar field potentials and put constraints on the coupling parameter between neutrinos and dark energy. Assuming the flatness of the universe, the constraint we can derive from the current observation is Σ mν < 0.87eV at the 95 % confidence level for the sum over three species of neutrinos.

Sign in / Sign up

Export Citation Format

Share Document