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We study inhomogeneous magnetised cosmologies through the post-recombination era in the framework of Newtonian gravity and the ideal-magnetohydrodynamic limit. The nonlinear kinematic and dynamic equations are derived and linearised around…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-02 Hera Vasileiou , Christos G. Tsagas

A critical discussion of our knowledge about extragalactic cosmic rays and magnetic fields is attempted. What do we know for sure? What are our prejudices? How do we confront our models with the observations? How can we assess the…

Astrophysics · Physics 2007-05-23 Torsten Ensslin

After a short introduction on how we get information of the magnetic fields from radio observations I discuss the results concerning the magnetic field structure in galaxies: Large-scale regular magnetic field pattern of spiral structure…

Astrophysics · Physics 2007-05-23 M. Krause

Magnetic fields in large scale structure filaments beyond galaxy clusters remain poorly understood. Superclusters offer a unique setting to study these low density environments, where weak signals make detection challenging. The Faraday…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-13 G. V. Pignataro , S. P. O'Sullivan , A. Bonafede , G. Bernardi , F. Vazza , E. Carretti

The amplitude of the magnetic field near the Galactic Centre has been uncertain by two orders of magnitude for several decades. On a scale of approximately 100 pc fields of approximately 1000 microG have been reported, implying a magnetic…

Astrophysics of Galaxies · Physics 2010-01-11 Roland M. Crocker , David Jones , Fulvio Melia , Jürgen Ott , Raymond J. Protheroe

We study the Faraday rotation measure (RM) due to the Galactic magnetic field (GMF) toward high Galactic latitudes. The RM arises from the global, regular component as well as from the turbulent, random component of the GMF. We model the…

Astrophysics of Galaxies · Physics 2015-06-15 Takuya Akahori , Dongsu Ryu , Jongsoo Kim , B. M. Gaensler

Primordial magnetic fields could provide an explanation for the galactic magnetic fields observed today, in which case they may also leave interesting signals in the CMB and the small-scale matter power spectrum. We discuss how to…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-26 J. Richard Shaw , Antony Lewis

We present a careful assess of the forced field extrapolation using Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) magnetogram. The convergence property is checked by several metrics. The extrapolated field lines…

Solar and Stellar Astrophysics · Physics 2017-03-22 Xiaoshuai Zhu , Huaning Wang , Zhanle Du , Han He

Magnetic fields of debated origin appear to permeate the Universe on all large scales. There is mounting evidence that supernovae produce not only roughly spherical ejecta and winds, but also highly relativistic jets of ordinary matter.…

Astrophysics · Physics 2009-11-11 Arnon Dar , A. De Rujula

The discovery of distant sources of very high energy (VHE) gamma-rays with hard energy spectra enabled to derive strong upper limits on the density of the extragalactic background light (EBL). These limits are close to the lower limits…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-05 M. Raue

This paper presents scale invariant/self-similar galactic magnetic dynamo models based on the classic equations, and compares them qualitatively to recently observed magnetic fields in edge-on spiral galaxies. We classify the axially…

Astrophysics of Galaxies · Physics 2021-11-03 R. H. Henriksen , Judith Irwin

The aim of the present work is to constrain the Coma cluster magnetic field strength, its radial profile and power spectrum by comparing Faraday Rotation Measure (RM) images with numerical simulations of the magnetic field. We have analyzed…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 A. Bonafede , L. Feretti , M. Murgia , F. Govoni , G. Giovannini , D. Dallacasa , K. Dolag , G. B. Taylor

(abridged) We investigate the possibility to recognize the magnetic field structures in nearby galaxies and to test the cosmological evolution of their large- and small-scale magnetic fields with the SKA and its precursors. We estimate the…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-18 T. G. Arshakian , R. Stepanov , R. Beck , M. Krause , D. Sokoloff , P. Frick

We use recent measurements of the dimensionless coordinate distances from Fanaroff-Riley Type IIb radio galaxies and the X-ray gas mass fractions in clusters to constrain the parameters of a non-standard cosmological model. This work…

Astrophysics · Physics 2009-04-03 Dirk Puetzfeld , Martin Pohl , Zong-Hong Zhu

We assess the principal statistical and physical uncertainties associated with the determination of magnetic field strengths in clusters of galaxies from measurements of Faraday rotation (FR) and Compton-synchrotron emissions. In the former…

Astrophysics · Physics 2009-11-07 William I. Newman , Alice L. Newman , Yoel Rephaeli

Context. Studies on compact galaxy groups have led to the conclusion that a plenitude of phenomena take place in between galaxies that form them. However, radio data on these objects are extremely scarce and not much is known concerning the…

Astrophysics of Galaxies · Physics 2017-07-12 B. Nikiel Wroczyński , M. Urbanik , M. Soida , R. Beck , D. J. Bomans

We have measured the Zeeman splitting of OH megamaser emission at 1667 MHz from five (ultra)luminous infrared galaxies ([U]LIRGs) using the 305 m Arecibo telescope and the 100 m Green Bank Telescope. Five of eight targeted galaxies show…

Astrophysics · Physics 2009-11-13 Timothy Robishaw , Eliot Quataert , Carl Heiles

Radio observations provide a powerful tool to constrain the assembly of galaxies over cosmic time. Recent deep and wide radio continuum surveys have improved significantly our understanding on radio emission properties of AGNs and SFGs…

Astrophysics of Galaxies · Physics 2025-02-19 Fangyou Gao , Tao Wang , Yijun Wang

We discuss a model of formation of extragalactic radio sources when the parent optical galaxy has a large-scale dipolar magnetic field. The study of dynamics of ejected from the central part of optical galaxy clouds of relativistic…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-30 R. R. Andreasyan

We briefly review sources of cosmic rays, their composition and spectra as well as their propagation in the galactic and extragalactic magnetic fields, both regular and fluctuating. A special attention is paid to the recent results of the…

High Energy Astrophysical Phenomena · Physics 2012-05-09 Felix Aharonian , Andrei Bykov , Etienne Parizot , Vladimir Ptuskin , Alan Watson