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Persistent activity of magnetars is associated with electric discharge that continually injects relativistic particles into the magnetosphere. Large active magnetic loops around magnetars must be filled with outflowing particles that…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Andrei M. Beloborodov

We observe the anisotropy of the power spectral tensor of magnetic field fluctuations in the fast solar wind for the first time. In heliocentric RTN coordinates the power in each element of the tensor has a unique dependence on the angle…

Space Physics · Physics 2015-05-30 Robert T. Wicks , Miriam A. Forman , Timothy S. Horbury , Sean Oughton

The local Galactic HI gas was found to contain cold neutral medium (CNM) filaments that are aligned with polarized dust emission. These filaments appear to be dominated by the magnetic field and in this case turbulence is expected to show…

Astrophysics of Galaxies · Physics 2016-10-26 P. M. W. Kalberla , J. Kerp

By means of three dimensional high-resolution hybrid simulations we study the properties of the magnetic field spectral anisotropies near and beyond ion kinetic scales. By using both a Fourier analysis and a local analysis based on…

Solar and Stellar Astrophysics · Physics 2019-04-18 Simone Landi , Luca Franci , Emanuele Papini , Andrea Verdini , Lorenzo Matteini , Petr Hellinger

A key prediction of turbulence theories is frame-invariance, and in magnetohydrodynamic (MHD) turbulence, axisymmetry of fluctuations with respect to the background magnetic field. Paradoxically the power in fluctuations in the turbulent…

Solar and Stellar Astrophysics · Physics 2011-10-14 A. J. Turner , G. Gogoberidze , S. C. Chapman , B. Hnat , W. -C. Mueller

The radio continuum spectra of 14 star-forming galaxies are investigated by fitting nonthermal (synchrotron) and thermal (free-free) radiation laws. The underlying radio continuum measurements cover a frequency range of ~325 MHz to 24.5 GHz…

Astrophysics of Galaxies · Physics 2018-03-28 Uli Klein , Ute Lisenfeld , Simon Verley

Recently, in a few case studies we demonstrated that gyrosynchrotron microwave emission can be detected directly from the acceleration region when the trapped electron component is insignificant. For the statistical study reported here, we…

Solar and Stellar Astrophysics · Physics 2016-07-27 Gregory D. Fleishman , Gelu M. Nita , Eduard P. Kontar , Dale E. Gary

Synchrotron emission of relativistic particles in magnetic fields is a process of paramount importance in astrophysics. Although known for over thirty years, there are still aspects of this radiative process that have received little…

Astrophysics · Physics 2009-11-07 Roberto Aloisio , Pasquale Blasi

A relationship is derived between power anisotropy and wavevector anisotropy in turbulent fluctuations. This can be used to interpret plasma turbulence measurements, for example in the solar wind. If fluctuations are anisotropic in shape…

Plasma Physics · Physics 2012-08-17 C. H. K. Chen , R. T. Wicks , T. S. Horbury , A. A. Schekochihin

We present a complete solution to the cyclotron-synchrotron radiation due to an isotropic distribution of electrons moving in a magnetic field. We make no approximations in the calculations other than artificially broadening the harmonics…

Astrophysics · Physics 2009-10-28 Rohan Mahadevan , Ramesh Narayan , Insu Yi

The thermal emission from isolated neutron stars is not well understood. The X-ray spectrum is very close to a blackbody but there is a systematic optical excess flux with respect to the extrapolation to low energy of the best blackbody…

Astrophysics · Physics 2009-11-13 J. F. Perez-Azorin , J. A. Miralles , J. A. Pons

We present a set of three-dimensional (3D) direct numerical simulations of incompressible decaying magnetohydrodynamic turbulence in which we investigate the influence of an external uniform magnetic field B_0. A parametric study in terms…

Fluid Dynamics · Physics 2009-11-13 Barbara Bigot , Sebastien Galtier , Helene Politano

Soft cyclo-synchrotron photons produced by thermal electrons moving in a magnetic field can be subsequently Comptonized to produce hard X-ray and $\gamma$-ray emission. An accurate determination of the amount of soft cyclo-synchrotron…

Astrophysics · Physics 2007-05-23 Rohan Mahadevan

When an emitting spherical shell with a constant Lorentz factor turns off emission abruptly at some radius, its high-latitude emission would obey the relation of $\hat{\alpha}$ (the temporal index) = $2 + \hat{\beta}$ (the spectral index).…

High Energy Astrophysical Phenomena · Physics 2018-01-16 Jin-Jun Geng , Yong-Feng Huang , Zi-Gao Dai

The results of the experiments on recording hard gamma radiation and measurements of its angular distribution at the initial stage of a laboratory high-voltage atmospheric discharge are presented. The experiments were performed on an ERG…

Plasma Physics · Physics 2018-07-23 A. V. Agafonov , A. V. Oginov , A. A. Rodionov , V. A. Ryabov , V. A. Chechin , K. V. Shpakov

We present the first targeted measurement of the power spectrum of anisotropies of the radio synchrotron background, at 140 MHz where it is the overwhelmingly dominant photon background. This measurement is important for understanding the…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-06 A. R. Offringa , J. Singal , S. Heston , S. Horiuchi , D. M. Lucero

The existing theoretical framework for the energies stored in the synchrotron-emitting lobes of radio galaxies and quasars doesn't properly account for the curved spectral shape that many of them exhibit. We characterise these spectra using…

Astrophysics of Galaxies · Physics 2015-06-03 Peter Duffy , Katherine M. Blundell

We develop a self-consistent model of Seyfert galaxies continuum emission. High energy emission is produced by Inverse Compton process on soft photons emitted as thermal radiation by the accretion disk. Thermal emission is, at turn,…

Astrophysics · Physics 2009-10-30 P. O. Petrucci , G. Henri , J. Malzac , E. Jourdain

The spectral index of synchrotron emission is an important parameter in understanding the properties of cosmic ray electrons (CREs) and the interstellar medium (ISM). We determine the synchrotron spectral index ($\alpha_{\rm nt}$) of four…

Astrophysics of Galaxies · Physics 2015-06-24 Aritra Basu , Rainer Beck , Philip Schmidt , Subhashis Roy

Despite extensive observational and theoretical efforts, the physical processes responsible for shaping the diversity of accelerated electron spectra observed in solar flares remain poorly understood. We use 2D particle-in-cell (PIC)…

Solar and Stellar Astrophysics · Physics 2025-10-01 Martín Astete , Mario Riquelme , Daniel Verscharen