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We present new 3D magnetohydrodynamic (MHD) simulations of a supernova-driven, stratified interstellar medium. These simulations were run using the Waagan (2009) positivity preserving scheme for ideal MHD implemented in the Flash code. The…

Magnetic fields are critical at many scales to galactic dynamics and structure, including multiphase pressure balance, dust processing, and star formation. Dynamo action determines their dynamical structure and strength. Simulations of…

Observationally, magnetic fields reach equipartition with thermal energy and cosmic rays in the interstellar medium of disk galaxies such as the Milky Way. However, thus far cosmological simulations of the formation and evolution of…

星系天体物理 · 物理学 2015-06-18 R. Pakmor , F. Marinacci , V. Springel

Cosmic ray (CR) currents through magnetised plasma drive strong instabilities producing amplification of the magnetic field. This amplification helps explain the CR energy spectrum as well as observations of supernova remnants and radio…

高能天体物理现象 · 物理学 2017-07-31 James H. Matthews , Anthony R. Bell , Katherine M. Blundell , Anabella T. Araudo

We performed the first numerical simulations of magnetorotational instability from a sub-magnetar-class seed magnetic field in core collapse supernovae. As a result of axisymmetric ideal MHD simulations, we found that the magnetic field is…

高能天体物理现象 · 物理学 2015-06-15 Hidetomo Sawai , Shoichi Yamada , Hideyuki Suzuki

Aims. We investigate the cosmological evolution of large- and small-scale magnetic fields in galaxies in the light of present models of formation and evolution of galaxies. Methods. We use the dynamo theory to derive the timescales of…

天体物理学 · 物理学 2009-11-13 Tigran G. Arshakian , Rainer Beck , Marita Krause , Dmitry Sokoloff

We present results of 2D and 3D PIC simulations of magnetic turbulence production by isotropic cosmic-ray ions drifting upstream of SNR shocks. The studies aim at testing recent predictions of a strong amplification of short wavelength…

天体物理学 · 物理学 2009-11-13 Jacek Niemiec , Martin Pohl , Thomas Stroman , and Ken-Ichi Nishikawa

We investigate the cosmological evolution of large- and small-scale magnetic fields in galaxies at high redshifts. Results from simulations of hierarchical structure formation cosmology provide a tool to develop an evolutionary model of…

天体物理学 · 物理学 2009-11-13 Tigran G. Arshakian , Rainer Beck , Marita Krause , Dmitry Sokoloff

We present high resolution simulations of a multiple merger of three disk galaxies including the evolution of magnetic fields performed with the N-body/SPH code Gadget. For the first time, we embed the galaxies in a magnetized, low-density…

星系天体物理 · 物理学 2015-05-20 H. Kotarba , H. Lesch , K. Dolag , T. Naab , P. H. Johansson , J. Donnert , F. A. Stasyszyn

In star-forming galaxies, the far-infrared (FIR) and radio-continuum luminosities obey a tight empirical relation over a large range of star-formation rates (SFR). We examine magneto-hydrodynamic galaxy simulations with cosmic rays (CRs),…

星系天体物理 · 物理学 2022-07-20 Christoph Pfrommer , Maria Werhahn , Rüdiger Pakmor , Philipp Girichidis , Christine M. Simpson

Magnetic fields have been included in cosmological simulations of galaxy formation only recently, due to advances in numerical techniques and a better understanding of the galaxy formation physics. In this paper, we develop a new subgrid…

星系天体物理 · 物理学 2022-05-13 Yuankang Liu , Michael Kretschmer , Romain Teyssier

The universe is permeated by magnetic fields, with strengths ranging from a femtogauss in the voids between the filaments of galaxy clusters to several teragauss in black holes and neutron stars. The standard model behind cosmological…

It is widely known that cosmic magnetic fields, i.e. the fields of planets, stars, and galaxies, are produced by the hydromagnetic dynamo effect in moving electrically conducting fluids. It is less well known that cosmic magnetic fields…

天体物理学 · 物理学 2009-05-13 Frank Stefani , Agris Gailitis , Gunter Gerbeth

The global-scale dynamo action achieved in a simulation of a Sun-like star rotating at thrice the solar rate is assessed. The 3-D MHD Anelastic Spherical Harmonic (ASH) code, augmented with a viscosity minimization scheme, is employed to…

太阳与恒星天体物理 · 物理学 2015-03-17 Kyle Augustson , Sacha Brun , Mark Miesch , Juri Toomre

We present results from high-resolution hydrodynamic simulations of isolated SMC- and Milky Way-sized galaxies that include a model for feedback from galactic cosmic rays (CRs). We find that CRs are naturally able to drive winds with mass…

星系天体物理 · 物理学 2015-06-17 C. M. Booth , Oscar Agertz , Andrey V. Kravtsov , Nickolay Y. Gnedin

Magnetic fields can play a major role in the dynamics of outstanding explosions associated to violent events such as GRBs and hypernovae, since they provide a natural mechanism to harness the rotational energy of the central proto-neutron…

高能天体物理现象 · 物理学 2021-08-04 Matteo Bugli , Jérôme Guilet , Martin Obergaulinger

Core convection and dynamo activity deep within rotating A-type stars of 2 solar masses are studied with 3--D nonlinear simulations. Our modeling considers the inner 30% by radius of such stars, thus capturing within a spherical domain the…

天体物理学 · 物理学 2008-11-26 Allan Sacha Brun , Matthew K. Browning , Juri Toomre

The interstellar medium of the Milky Way and nearby disk galaxies harbours large-scale coherent magnetic fields of Microgauss strength, that can be explained via the action of a mean-field dynamo. As in our previous work, we aim to quantify…

星系天体物理 · 物理学 2020-03-18 Oliver Gressel , Detlef Elstner

We present results of 3D numerical simulations of magnetically confined, radiatively driven stellar winds of massive stars, conducted using the astrophysical MHD code Pluto, with a focus on understanding the rotational variability of radio…

太阳与恒星天体物理 · 物理学 2017-12-01 Simon Daley-Yates , Ian Stevens

We present two-dimensional, cylindrically symmetric simulations of hydrodynamic and magnetohydrodynamic (MHD) wide-angle winds interacting with a collapsing environment. These simulations have direct relevance to young stellar objects…

天体物理学 · 物理学 2009-11-07 T. A. Gardiner , A. Frank , L. Hartmann