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Galactic cosmic rays are believed to be accelerated at supernova remnants. However, whether supernova remnants can be Pevatrons is still very unclear. In this work we argue that PeV cosmic rays can be accelerated during the early phase of a…

高能天体物理现象 · 物理学 2021-11-24 Tsuyoshi Inoue , Alexandre Marcowith , Gwenael Giacinti , Allard Jan van Marle , Shogo Nishino

Using a set of cosmological hydro-dynamical simulations, we constrained the properties of primordial magnetic fields by studying their impact on the formation and evolution of dwarf galaxies. We performed a large set of simulations (8 dark…

星系天体物理 · 物理学 2020-11-04 Mahsa Sanati , Yves Revaz , Jennifer Schober , Kerstin E. Kunze , Pascale Jablonka

We discuss the damping of strong magnetic turbulence downstream of the forward shock of young supernova remnants (SNR). We find that strong magnetic fields, that have been produced by the streaming instability in the upstream region of the…

天体物理学 · 物理学 2009-11-10 M. Pohl , H. Yan , A. Lazarian

Cosmic rays are energetic nuclei that permeate the entire Galactic disk. Their existence requires the presence of powerful particle accelerators. While Galactic supernova explosions may supply the required energy, there is growing evidence…

高能天体物理现象 · 物理学 2024-07-11 Giada Peron , Sabrina Casanova , Stefano Gabici , Vardan Baghmanyan , Felix Aharonian

Magnetic fields play an important role in astrophysical accretion discs, and in the interstellar and intergalactic medium. They drive jets, suppress fragmentation in star-forming clouds and can have a significant impact on the accretion…

等离子体物理 · 物理学 2016-12-30 Christoph Federrath

(abridged abstract) Theoretical arguments indicate that close-in terrestial exoplanets may have weak magnetic fields, especially in the case of planets more massive than Earth (super-Earths). Planetary magnetic fields, however, constitute…

地球与行星天体物理 · 物理学 2015-09-03 J. -M. Grießmeier , F. Tabataba-Vakili , A. Stadelmann , J. L. Grenfell , D. Atri

A significant fraction of massive main-sequence stars show strong, large-scale magnetic fields. The origin of these fields, their lifetimes, and their role in shaping the characteristics and evolution of massive stars are currently not well…

太阳与恒星天体物理 · 物理学 2016-08-03 L. Fossati , F. R. N. Schneider , N. Castro , N. Langer , S. Simon-Diaz , A. Mueller , A. de Koter , T. Morel , V. Petit , H. Sana , G. A. Wade

The propagation of cosmic rays in turbulent magnetic fields is a diffusive process driven by the scattering of the charged particles by random magnetic fluctuations. Such fields are usually highly intermittent, consisting of intense…

高能天体物理现象 · 物理学 2017-04-19 Anvar Shukurov , Andrew Snodin , Amit Seta , Paul Bushby , Toby Wood

We study the generation of primordial magnetic fields, coherent over cosmologically interesting scales, by gravitational creation of charged scalar particles during the reheating period. We show that magnetic fields consistent with those…

高能物理 - 唯象学 · 物理学 2009-10-07 Alejandra Kandus , Esteban A. Calzetta , Francisco D. Mazzitelli , Carlos E. M. Wagner

The surface rotation rates of young solar-type stars vary rapidly with age from the end of the pre-main sequence through the early main sequence. Important changes in the dynamos operating in these stars may result from this evolution,…

太阳与恒星天体物理 · 物理学 2016-01-27 C. P. Folsom , P. Petit , J. Bouvier , A. Lèbre , L. Amard , A. Palacios , J. Morin , J. -F. Donati , S. V. Jeffers , S. C. Marsden , A. A. Vidotto

Most cosmic rays are thought to be accelerated by the shocks of supernova explosions of very massive stars. Here we review one quantitative proposal, which predicted the spectral slopes, bend and cutoff about the cosmic ray spectrum across…

天体物理学 · 物理学 2009-11-10 Peter L. Biermann

Magnetic fields are widely recognised as critical at many scales to galactic dynamics and structure, including multiphase pressure balance, dust processing, and star formation. Using imposed magnetic fields cannot reliably model the…

星系天体物理 · 物理学 2024-01-17 Frederick A. Gent , Mordecai-Mark Mac Low , Maarit J. Korpi-Lagg

It is presumed that the observed cosmic rays up to about $3\times 10^{18}$ eV are of Galactic origin, the particles being the ones which are found in the composition of the stellar winds of stars that explode as supernova into the…

天体物理学 · 物理学 2007-05-23 Adrian Sabin Popescu

The problem of the cosmic ray origin is discussed in connection with their acceleration in supernova remnant shocks. The diffusive shock acceleration mechanism is reviewed and its potential to accelerate particles to the maximum energy of…

天体物理学 · 物理学 2007-05-23 P. H. Diamond , M. A. Malkov

Magnetic fields are observed beyond the peripheries of optically detected galactic discs, while numerical models of their origin and the typical magnitudes are still absent. Previously, studies of galactic dynamo have avoided considering…

星系天体物理 · 物理学 2014-09-05 E. Mikhailov , A. Kasparova , D. Moss , R. Beck , D. Sokoloff , A. Zasov

We present a suite of high-resolution cosmological simulations, using the FIRE-2 feedback physics together with explicit treatment of magnetic fields, anisotropic conduction and viscosity, and cosmic rays (CRs) injected by supernovae…

Magnetic fields play a crucial role at all stages of the formation of low mass stars and planetary systems. In the final stages, in particular, they control the kinematics of in-falling gas from circumstellar discs, and the launching and…

太阳与恒星天体物理 · 物理学 2015-05-19 S. G. Gregory , M. Jardine , C. G. Gray , J. -F. Donati

While the presence of magnetic fields on low-mass stars is attributed to a dynamo process essentially driven by convective motions, the existence of magnetic fields on intermediate-mass stars has very likely other reasons. Presuming that…

太阳与恒星天体物理 · 物理学 2013-09-30 Rainer Arlt

The origin of large magnetic fields ($\gtrsim 10^6~\mathrm{G}$) in isolated white dwarfs is not clear. One possible explanation is that crystallization of the star's core drives compositional convection, which when combined with the star's…

太阳与恒星天体物理 · 物理学 2024-03-20 J. R. Fuentes , Matias Castro-Tapia , Andrew Cumming

Cosmic-ray energy densities in central regions of starburst galaxies, as inferred from radio and gamma-ray measurements of, respectively, non-thermal synchrotron and neutral pion decay emission, are typically U_p = O(100)eV/cm3, i.e.…

高能天体物理现象 · 物理学 2014-11-20 Massimo Persic , Yoel Rephaeli