Related papers: Limits for primordial magnetic fields
The large-scale structure of the Universe has been observed to be characterized by long filaments, forming polyhedra, with a remarkable 100-200 Mpc periodicity, suggesting a regular network. The introduction of magnetic fields into the…
Gravitational wave production induces a strong constraint on the amplitude of a primordial magnetic field. It has been shown that the nucleosynthesis bound for a stochastic gravitational wave background implies that causally generated…
We study primordial magnetic field effects on the matter perturbations in the Universe. We assume magnetic field generation prior to the big bang nucleosynthesis (BBN), i.e. during the radiation dominated epoch of the Universe expansion,…
Since magnetic fields in galaxies, galactic clusters and even void regions are observed, theoretical attempts to explain their origin are strongly motivated. It is interesting to consider that inflation is responsible for the origin of the…
We address the question of the existence of magnetic domains in a recent scenario for the creation of primordial magnetic fields. We write down the magnetohydrodynamic equation in an expanding universe in the infinite conductivity limit and…
The origin of cosmic magnetism is an issue of fundamental importance in astrophysics. We review here some of the ideas of how large scale magnetic fields in the universe, particularly in galaxies and galaxy clusters could arise. The popular…
Basically the only existing theories for the creation of a magnetic field B in the Universe are the creation of a seed field of order 10^{-20} G in spiral galaxy which is subsequently supposedly amplified up to the observed 10^{-6} -…
The galactic magnetic field is commonly supposed to be due to a dynamo acting on some large scale seed field. A major difficulty with this idea is that estimates of reasonable seed field strengths tend to be quite low, on the order of…
Magnetic fields are ubiquitous in the Universe. Extragalactic disks, halos and clusters have consistently been shown, via diffuse radio-synchrotron emission and Faraday rotation measurements, to exhibit magnetic field strengths ranging from…
The origin of magnetic fields observed on both astrophysical and cosmological scales is a compelling problem that has the potential to shed light on the early Universe. We analytically investigate inflationary magnetogenesis in scenarios…
It is usually assumed that when Weyl invariance is unbroken in the electromagnetic sector, the energy density of primordial magnetic fields will redshift as radiation. Here we show that primordial magnetic fields do not exhibit…
Different mechanisms which may possibly explain existence of magnetic fields on astronomically large scales are described. A recently suggested model of magnetic fields generation slightly before hydrogen recombination is discussed in more…
We consider Vachaspati's primordial magnetic field which is generated at the electroweak phase transition. Assuming that either the gradients of the Higgs field or, alternatively, the magnetic field itself are stochastic variables with a…
The origin of interstellar and intergalactic magnetic fields remains largely unknown. One possibility is that they are related to the primordial magnetic fields (PMFs) produced by, for instance, the phase transitions of the early Universe.…
Magnetic fields in galaxies are produced via the amplification of seed magnetic fields of unknown nature. The seed fields, which might exist in their initial form in the intergalactic medium, were never detected. We report a lower bound…
We consider the possibility that cosmic magnetic field, instead of being uniformly distributed, is strongly correlated with the large scale structure of the universe. Then, the observed rotational measure of extra-galactic radio sources…
The 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…
A primordial stochastic magnetic field will induce temperature and polarization fluctuations in the cosmic microwave background. We outline a calculation of the resulting fluctuation power spectra and present numerical results.
Possible existence of the primordial magnetic fields has affected the structure formation of the universe. In this paper it is shown that the initial conditions for density perturbations with magnetic fields derived in previous works are…
We give a pedagogical introduction to two aspects of magnetic fields in the early universe. We first focus on how to formulate electrodynamics in curved space time, defining appropriate magnetic and electric fields and writing Maxwell…