相关论文: Strong magnetic fields and cosmic rays in very you…
Newly born magnetars are good candidate sources of ultrahigh energy cosmic rays. These objects can in principle easily accelerate particles to the highest energies required to satisfy the ultrahigh energy cosmic ray scenario (E~10^{20-21}…
We review current ideas on the origin of galactic and extragalactic magnetic fields. We begin by summarizing observations of magnetic fields at cosmological redshifts and on cosmological scales. These observations translate into constraints…
The magnetic fields of spiral galaxies are so strong that they cannot be primordial. Their typical values are over one billion times higher than any value predicted for the early Universe. Explaining this immense growth and incorporating it…
Are the kG-strength magnetic fields observed in young stars a fossil field left over from their formation or are they generated by a dynamo? We use radiation non-ideal magnetohydrodynamics simulations of the gravitational collapse of a…
We investigate the cosmological evolution of large- and small-scale magnetic fields in galaxies at high redshifts. Results from simulations of hierarchical structure formation cosmology provide a tool to develop an evolutionary model of…
In this paper we show that the Universe is already strongly magnetized at very early epochs during cosmic evolution. Our calculations are based on the efficient amplification of weak magnetic seed fields, which are unavoidably present in…
Observations have shown the existence of narrow, very long, straight jets emitted by some newly forming stars (1). It is highly likely that stars forming in the plane of a spiral galaxy do so in the presence of an almost uniform magnetic…
We discuss processes in galactic cosmic ray (GCR) acceleration sites - supernova remnants, compact associations of young massive stars, and superbubbles. Mechanisms of efficient conversion of the mechanical power of the outflows driven by…
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…
We present three-dimensional global numerical simulations of the cosmic-ray (CR) driven dynamo in barred galaxies. We study the evolution of the interstellar medium of the barred galaxy in the presence of non-axisymmetric component of the…
Galactic magnetic fields in the local Universe are strong and omnipresent. There is mounting evidence that galaxies were magnetized already in the early Universe. Theoretical scenarios including the turbulent small-scale dynamo predict…
Arguably the main challenge of galactic magnetism studies is to explain how the interstellar medium of galaxies reaches energetic equipartition despite the extremely weak cosmic primordial magnetic fields that are originally predicted to…
Observations of magnetism in very low mass stars recently made important progress, revealing characteristics that are now to be understood in the framework of dynamo theory. In parallel, there is growing evidence that dynamo processes in…
Observations of Faraday rotation through high-redshift galaxies have revealed that they host coherent magnetic fields that are of comparable strengths to those observed in nearby galaxies. These fields could be generated by fluctuation…
The long-held notion that the highest-energy cosmic rays are of distant extragalactic origin is challenged by observations that events above $\sim 10^{20}$ eV do not exhibit the expected high-energy cutoff from photopion production off the…
The small-scale turbulent dynamo is an important process contributing to the cosmic magnetization. In partially ionized astrophysical plasmas, the dynamo growth of magnetic energy strongly depends on the coupling state between ions and…
Natural dynamos such as planets and stars generate global scale magnetic field despite the inferred presence of small scale turbulence. Such systems are known as large scale dynamos and are typically driven by convection and influenced by…
We propose that the overlapping shock fronts from young supernova remnants produce a locally unsteady, but globally steady large scale spiral shock front in spiral galaxies, where star formation and therefore massive star explosions…
Deep observations are revealing a growing number of young galaxies in the first billion year of cosmic time. Compared to typical galaxies at later times, they show more extreme emission-line properties, higher star formation rates, lower…
High-redshift primordial galaxies have recently been found with evolved stellar populations and complex star-formation histories reaching back to 250 Myr after the Big Bang. Their intense bursts of star-formation appear to be interspersed…