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$\gamma$-ray emission of blazars infer the presence of large-scale magnetic fields in the intergalactic medium, but their origin remains a mystery. Using recent data from MAGIC, H.E.S.S. and $\textit{Fermi}$-LAT, we investigate whether the…

High Energy Physics - Phenomenology · Physics 2024-05-07 María Olalla Olea-Romacho

Observations of the Milky Way and external galaxies support the idea that large-scale magnetic fields are concentrated in galactic disks, with halo magnetic fields at least an order of magnitude weaker. However, very little is known about…

Astrophysics of Galaxies · Physics 2025-03-04 Bailey Forster , Tyler J. Foster , Roland Kothes , Alex S. Hill , Jo-Anne Brown

Polarization data from high mass star formation regions (W51 e2/e8, Orion BN/KL) are used to derive statistical properties of the plane of sky projected magnetic field. Structure function and auto-correlation function are calculated for…

Solar and Stellar Astrophysics · Physics 2015-05-19 Patrick M. Koch , Ya-Wen Tang , Paul T. P. Ho

Marked statistics allow sensitive tests of how galaxy properties correlate with environment, as well as of how correlations between galaxy properties are affected by environment. A halo-model description of marked correlations is developed,…

Astrophysics · Physics 2009-11-16 Ravi K. Sheth

We focus on the complex relationship between the shape of dark matter halos and the cosmological models underlying their formation. We used three realistic cosmological models from the Dark Energy Universe Simulation suite. They have…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-30 Jean-Michel Alimi , Remy Koskas

We report a measurement of intergalactic magnetic fields using combined data from Atmospheric Cherenkov Telescopes and Fermi Gamma-Ray Space Telescope, based on the spectral data alone. If blazars are assumed to produce both gamma rays and…

High Energy Astrophysical Phenomena · Physics 2012-04-03 Warren Essey , Shin'ichiro Ando , Alexander Kusenko

The forthcoming new-generation radio telescope SKA (Square Kilometre Array) and its precursors will provide a rapidly growing number of polarized radio sources. Our analysis aims on what can be learned from these sources concerning the…

Astrophysics · Physics 2009-11-13 Rodion Stepanov , Tigran G. Arshakian , Rainer Beck , Peter Frick , Marita Krause

A fully three-dimensional (3D) magnetohydrodynamical (MHD) model is applied to simulate the evolution of the large-scale magnetic field in cluster galaxies interacting with the intra-cluster medium (ICM). As the model input we use a time…

Astrophysics · Physics 2011-05-23 K. Otmianowska-Mazur , B. Vollmer

Magnetic fields play an important role in shaping the structure and evolution of the interstellar medium (ISM) of galaxies, but the details of this relationship remain unclear. With SKA1, the 3D structure of galactic magnetic fields and its…

In Paper I we showed that multi-phase gaseous halos of late-type spiral galaxies, detected in the radio continuum, in Halpha, and in X-rays, are remarkably well correlated regarding their morphology and spatial extent. In this work we…

Astrophysics · Physics 2008-11-26 R. Tuellmann , D. Breitschwerdt , J. Rossa , W. Pietsch , R. -J. Dettmar

Helicity and \alpha effect driven by the nonaxisymmetric Tayler instability of toroidal magnetic fields in stellar radiation zones are computed. In the linear approximation a purely toroidal field always excites pairs of modes with…

Solar and Stellar Astrophysics · Physics 2015-05-28 G. Ruediger , L. L. Kitchatinov , D. Elstner

Magnetic fields in galaxy clusters can be investigated using a variety of techniques. Recent studies including radio halos, Inverse Compton hard X-ray emissions and Faraday rotation measure, are briefly outlined. A numerical approach for…

Astrophysics · Physics 2007-05-23 Federica Govoni , Matteo Murgia

We study the possibility that primordial magnetic fields generated in the transition between inflation and reheating posses magnetic helicity, $H_M$. The fields are induced by stochastic currents of scalar charged particles created during…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-07 Esteban Calzetta , Alejandra Kandus

The statistical properties of dark matter halos, the building blocks of cosmological observables associated with structure in the universe, offer many opportunities to test models for cosmic acceleration, especially those that seek to…

Astrophysics · Physics 2009-10-02 Fabian Schmidt , Marcos Lima , Hiroaki Oyaizu , Wayne Hu

Image flux ratio anomalies have been attributed to substructures within the gravitational lens and to small mass halos (M <~ 10^10 Msun) in intergalactic space. In this paper, analytic calculations are presented that help in the…

Astrophysics · Physics 2015-06-24 R. Benton Metcalf

We seek the conditions for a {\it steady} mean field galactic dynamo. The parameter set is reduced to those appearing in the $\alpha^2$ and $\alpha/\omega$ dynamo, namely velocity amplitudes, and the ratio of sub-scale helicity to…

Astrophysics of Galaxies · Physics 2017-06-28 R. N. Henriksen

We here report calculations of magnetic buoyancy instabilities of a sheared magnetic layer where two separate zones are unstable. The idea is to study the possible generation of large-scale helical structures which could then rise through a…

Solar and Stellar Astrophysics · Physics 2012-10-31 L. Jouve , L. J. Silvers , M. R. E. Proctor

We demonstrate a new way of studying interplanetary magnetic field -- Ground State Alignment (GSA). Instead of sending thousands of space probes, GSA allows magnetic mapping with any ground telescope facilities equipped with…

Instrumentation and Methods for Astrophysics · Physics 2012-10-03 Jinyi Shangguan , Huirong Yan

In the present work we study the statistics of haloes, which in the halo model determines the distribution of galaxies. Haloes are known to be biased tracer of dark matter, and at large scales it is usually assumed there is no intrinsic…

Astrophysics · Physics 2015-05-13 Silvia Bonoli , Ue-Li Pen

Magnetic helicity, and more broadly magnetic field line topology, impose constraints on the plasma dynamics. Helically interlocked magnetic rings are in a non-trivial topological state. It is harder to bring them into a topologically…

Plasma Physics · Physics 2024-12-09 Simon Candelaresi , Fabio Del Sordo