Generation of the Primordial Magnetic Fields during Cosmological Reionization

By Nickolay Y. Gnedin, A. Ferrara, E. Zweibel. 2000

178 citations recorded by the source corpus.

We investigate the generation of magnetic fields by the Biermann battery in cosmological ionization fronts, using new simulations of the reionization of the universe by stars in protogalaxies. Two mechanisms are primarily responsible for magnetogenesis: (1) the breakout of ionization fronts from protogalaxies and (2) the propagation of ionization fronts through the high-density neutral filaments that are part of the cosmic web. The first mechanism is dominant prior to overlapping of ionized regions (z ≈ 7), whereas the second continues to operate even after that epoch. However, after overlap the field strength increase is largely due to the gas compression occurring as cosmic structures form. As a consequence, the magnetic field at z ≈ 5 closely traces the gas density, and it is highly ordered on megaparsec scales. The mean mass-weighted field strength is B0 ≈ 10-19 G in the simulation box. There is a relatively well-defined, nearly linear correlation between B0 and the baryonic mass of virialized objects, with B0 ≈ 10-18 G in the most massive objects (M ≈ 109 M☉) in our simulations. This is a lower limit, as lack of numerical resolution prevents us from following small-scale dynamical processes that could amplify the field in protogalaxies. Although the field strengths we compute are probably adequate as seed fields for a galactic dynamo, the field is too small to have had significant effects on galaxy formation, on thermal conduction, or on cosmic-ray transport in the intergalactic medium. It could, however, be observed in the intergalactic medium through innovative methods based on analysis of γ-ray burst photon arrival times.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/d1045aca0d90d37c8c81a7d110caba98b8225ed5

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Citations in the corpus

THE MASS SPECTRUM OF THE FIRST STARS (2014, background): “…the initial field strength, which can affect the dynamics of the star formation, is larger than the expected seed field strength in cosmological context (e.g., Gnedin et al. 2000; Turner& Widrow 1988; Ichiki et al. 2006; Xu et al. 2008; Ando et al. 2010; Doi & Susa 2011; Shiromoto et al. 2014).”
Magnetic Fields in Galaxies (2010, background): “Examples of top down theories based on conventional physics are magnetization by the Biermann battery in cosmological ionization fronts or cosmological shock fronts (Kulsrud et al. 1997, Gnedin et al. 2000).”
EGMF Constraints from Simultaneous GeV-TeV Observations of Blazars (2011, methodology): “It is possible that the seed fields are produced locally in (proto)galaxies via the so-called “Biermann battery” mechanism (Pudritz & Silk 1989; Gnedin et al. 2000).”
Astrophysical magnetic fields and nonlinear dynamo theory (2004, background): “[185] found a mean mass-weighted field strength of B ∼ 10−19 G in their simulation box.”
Extreme TeV blazars and the intergalactic magnetic field (2010, background): “…those considering effects occurring during the inflation (e.g. Turner & Widrow 1988) or phase transition era in the Early Universe (e.g. Kahniashvili et al. 2011 and references therein) to those invoking mechanisms active during the early stages of protogalaxy formation (e.g. Gnedin et al. 2000).”
Cosmological Magnetic Fields: Their Generation, Evolution and Observation (2013, background): “Possible mechanisms for the generation of magnetic fields during the gravitational collapse are the Weibel instability (Schlickeiser and Shukla 2003; Medvedev et al 2006) or battery effects (Subramanian et al 1994; Kulsrud et al 1997; Gnedin et al 2000).”
Cluster Magnetic Fields (2001, background): “28 Cluster Magnetic Fields turbulent dynamo processes and/or shocks occurring during structure formation (Zweibel 1988; Kulsrud et al. 1997; Waxman & Loeb 2000), or by battery effects during the epoch of reionization (Gnedin et al. 2000).”