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We explore the ways in which primordial magnetic fields influence the thermal and ionization history of the post-recombination universe. After recombination the universe becomes mostly neutral resulting also in a sharp drop in the radiative…

Astrophysics · Physics 2008-11-26 Shiv K. Sethi , Kandaswamy Subramanian

Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which…

Solar and Stellar Astrophysics · Physics 2015-06-24 Lilia Ferrario , Andrew Melatos , Jonathan Zrake

We point out that the lower bound on the primordial magnetic field required to seed the galactic dynamo is significantly relaxed in an open universe or in a universe with a positive cosmological constant. It is shown that, for reasonable…

Astrophysics · Physics 2008-11-26 Anne-Christine Davis , Matthew Lilley , Ola Tornkvist

Primordial magnetic fields may account for all or part of the fields observed in galaxies. We consider the evolution of the magnetic fields created by pseudoscalar effects in the early universe. Such processes can create force-free fields…

Astrophysics · Physics 2009-10-31 George B. Field , Sean M. Carroll

Magnetism is one of the four fundamental forces. However, the origin of magnetic fields in stars, galaxies and clusters is an open problem in astrophysics and fundamental physics. When and how were the first fields generated? Are…

Astrophysics · Physics 2009-11-10 B. M. Gaensler , R. Beck , L. Feretti

Magnetic fields on a range of scales play a large role in the ecosystems of galaxies, both in the galactic disk and in the extended layers of gas away from the plane. Observing magnetic field strength, structure and orientation is complex,…

Astrophysics of Galaxies · Physics 2015-05-27 Marijke Haverkorn , Volker Heesen

Magnetic fields are ubiquitous in the universe and an important component of the interstellar medium. It is crucial to accurately model and understand their properties in different environments and across all mass ranges of galaxies to…

Astrophysics of Galaxies · Physics 2025-12-22 Maria Werhahn , Rüdiger Pakmor , Rebekka Bieri , Freeke van de Voort , Rosie Y. Talbot , Volker Springel

Magnetic fields are considered to be key components of massive stars, with a far-reaching impact on their evolution and ultimate fate. A magnetic mechanism was suggested for the collimated explosion of massive stars, relevant for…

Solar and Stellar Astrophysics · Physics 2024-10-28 Swetlana Hubrig , Markus Schöller , Silva P. Järvinen , Aleksandar Cikota , Michael Abdul-Masih , Ana Escorza , Ilya Ilyin

The origin of astrophysical magnetic fields observed in galaxies and clusters of galaxies is still unclear. One possibility is that primordial magnetic fields generated in the early Universe provide seeds that grow through compression and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 C. Fedeli , L. Moscardini

Microgauss magnetic fields are observed in all galaxies at low and high redshifts. The origin of these intense magnetic fields is a challenging question in astrophysics. We show here that the natural plasma fluctuations in the primordial…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-29 Rafael S. de Souza , R. Opher

The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few constraints on the timescale. It has…

The origin of large-scale magnetic fields, detected in some low-mass (dwarf and irregular) galaxies via polarised synchrotron emission and Faraday rotation, remained unexplained for a long time. We suggest that mean-field dynamo can be…

Astrophysics of Galaxies · Physics 2019-10-16 Prasanta Bera , Anvar Shukurov , Kandaswamy Subramanian

We propose a primordial-origin model for the composite configurations of global magnetic fields in spiral galaxies. We show that uniform tilted magnetic field wound up into a rotating disk galaxy can evolve into composite magnetic…

Astrophysics of Galaxies · Physics 2015-05-19 Yoshiaki Sofue , Mami Machida , Takahiro Kudoh

Early-type stars show a bimodal distribution of magnetic field strengths, with some showing very strong fields ($\gtrsim 1\,\mathrm{kG}$) and others very weak fields ($\lesssim 10\,\mathrm{G}$). Recently, we proposed that this reflects the…

Solar and Stellar Astrophysics · Physics 2021-12-22 Adam S. Jermyn , Matteo Cantiello

Magnetic fields are an important ingredient of the interstellar medium (ISM). Besides their importance for star formation, they govern the transport of cosmic rays, relevant to the launch and regulation of galactic outflows and winds, which…

Observations of stable mainly dipolar magnetic fields at the surface of ~7% of single hot stars indicate that these fields are of fossil origin, i.e. they descend from the seed field in the molecular clouds from which the stars were formed.…

Solar and Stellar Astrophysics · Physics 2015-02-03 C. Neiner , S. Mathis , E. Alecian , C. Emeriau , J. Grunhut , the BinaMIcS , MiMeS collaborations

In this paper we study the effect of a magnetic field on the fluctuation spectrum of the cosmic microwave background. We find that upcoming measurements might give interesting bounds on large scale magnetic fields in the early Universe. If…

Astrophysics · Physics 2009-10-28 Jenni Adams , Ulf H. Danielsson , Dario Grasso , Héctor Rubinstein

Beginning with cosmological initial conditions at z=100, we simulate the effects of magnetic fields on the formation of Population III stars and compare our results with the predictions of Paper I. We use Gadget-2 to follow the evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-04 Athena Stacy , Christopher F. McKee , Aaron T. Lee , Richard I. Klein , Pak Shing Li

The effect of primordial magnetic fields on X-ray or S-Z galaxy cluster survey is investigated. After recombination, the primordial magnetic fields generate additional density fluctuations. Such density fluctuations enhance the number of…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-05 Hiroyuki Tashiro , Keitaro Takahashi , Kiyotomo Ichiki

From previous studies of the effect of primordial magnetic fields on early structure formation, we know that the presence of primordial magnetic fields during early structure formation could induce more perturbations at small scales (at…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Kanhaiya L. Pandey , Shiv K. Sethi
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