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Recent cosmological hydrodynamic simulations have suggested that the first stars in the universe often form as binary or multiple systems. However, previous studies typically overlooked the potential influence of magnetic fields during this…

Astrophysics of Galaxies · Physics 2024-05-27 Kenji Eric Sadanari , Kazuyuki Omukai , Kazuyuki Sugimura , Tomoaki Matsumoto , Kengo Tomida

The evolution of the magnetic field and angular momentum in the collapsing cloud core is studied using three-dimensional resistive MHD nested grid simulations. Starting with a Bonnor-Ebert isothermal cloud rotating in a uniform magnetic…

Astrophysics · Physics 2009-11-13 Masahiro N. Machida , Shu-ichiro Inutsuka , Tomoaki Matsumoto

Recent high-angular-resolution (up to 0.7") dust polarization observations toward star forming regions are summarized. With the Sub-Millimeter Array, the emission from the dense structures is traced and resolved. The detected magnetic field…

Astrophysics of Galaxies · Physics 2012-02-22 Ya-Wen Tang , Patrick M. Koch , Paul T. P. Ho

Magnetic fields are dynamically important in the diffuse interstellar medium. Understanding how gravitationally bound, star-forming clouds form requires modeling of the fields in a self-consistent, supernova-driven, turbulent, magnetized,…

Astrophysics of Galaxies · Physics 2022-02-16 Juan C. Ibáñez-Mejía , Mordecai-Mark Mac Low , Ralf S. Klessen

I review some steps in the conversion of molecular cloud gas into stars and planets, with an emphasis in this presentation on the early stage molecular cloud fragmentation that leads to elongated filaments/ribbons. Magnetic fields can play…

Astrophysics of Galaxies · Physics 2017-01-11 Shantanu Basu

We study the self-similar collapse of an isothermal magnetized rotating cloud in the ideal magnetohydrodynamic (MHD) regime. In the limit of small distance from the accreting protostar we find an analytic solution that corresponds to…

Astrophysics · Physics 2008-11-26 D. Galli , S. Lizano , F. H. Shu , A. Allen

The evolution of collapsing clouds embedded in different star-forming environments is investigated using three-dimensional non-ideal magnetohydrodynamics simulations considering different cloud metallicities ($Z/\thinspace Z_\odot$ = 0,…

Solar and Stellar Astrophysics · Physics 2019-04-24 Koki Higuchi , Masahiro N. Machida , Hajime Susa

Strong magnetic fields play a crucial role in the removal of angular momentum from collapsing clouds and protostellar discs and are necessary for the formation of disc winds as well as jets from the inner disc and indeed, strong large-scale…

Solar and Stellar Astrophysics · Physics 2015-06-03 Jonathan Braithwaite

Thermal ionization is a critical process at temperatures T > 10 3 K, particularly during star formation. An increase in ionization leads to a decrease in nonideal magnetohydrodynamics (MHD) resistivities, which has a significant impact on…

Solar and Stellar Astrophysics · Physics 2022-10-05 Pierre Marchand , Vincent Guillet , Ugo Lebreuilly , Mordecai-Mark Mac Low

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…

Solar and Stellar Astrophysics · Physics 2015-05-19 S. G. Gregory , M. Jardine , C. G. Gray , J. -F. Donati

The origin of supermassive black holes (with $\gtrsim\!10^9\,M_{\odot}$) in the early universe (redshift $z \sim 7$) remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but…

Astrophysics of Galaxies · Physics 2021-08-18 Shingo Hirano , Masahiro N. Machida , Shantanu Basu

In the inner regions of protoplanetary discs, ionization chemistry controls the fluid viscosity, and is thus key to understanding various accretion, outflow and planet formation processes. The ionization is driven by thermal and non-thermal…

Earth and Planetary Astrophysics · Physics 2024-11-25 Morgan Williams , Subhanjoy Mohanty

The breakdown of flux-freezing in molecular clouds and protostellar discs is usually approximated by ambipolar diffusion at low densities or by resistive diffusion at high densities. Here I discuss an intermediate regime in which the Hall…

Astrophysics · Physics 2009-11-10 Mark Wardle

Magnetic fields play an important role for the formation of stars in both local and high-redshift galaxies. Recent studies of dynamo amplification in the first dark matter haloes suggest that significant magnetic fields were likely present…

Astrophysics of Galaxies · Physics 2020-07-08 Piyush Sharda , Christoph Federrath , Mark R. Krumholz

Magnetic fields are believed to play an important role in controlling the stability and contraction of dense condensations of gas and dust leading to the formation of stars and planetary systems. In the present study, the magnetic field of…

Massive stars ($M > 8$ \msun) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster of stellar objects. We investigate the role of magnetic fields in this process through dust…

This paper shows that magnetic reconnection could be an important heating process in cosmic gases. In any volume where magnetized plasmas collide, the dissipation of magnetic energy via reconnection seems to be unavoidable. Since most…

Astrophysics · Physics 2007-05-23 F. Zimmer , H. Lesch , G. T. Birk

Polarization carries information about the magnetic fields in interstellar clouds. The observations of polarized dust emission are used to study the role of magnetic fields in the evolution of molecular clouds and the initial phases of…

Astrophysics of Galaxies · Physics 2015-05-13 V. -M. Pelkonen , M. Juvela , P. Padoan

We consider the dynamical evolution of an interstellar cloud that is initially in thermal equilibrium in the warm phase and is then subjected to a sudden increase in the pressure of its surroundings. We find that if the initial plasma beta…

Astrophysics · Physics 2009-11-13 A. J. Lim , S. A. E. G. Falle , T. W. Hartquist

Context: Filaments are common features in molecular clouds and they play a key role in star formation (SF). Studying their life cycle is essential to fully understand the SF process. Aims: We aim to characterise the impact of magnetic field…

Astrophysics of Galaxies · Physics 2025-05-07 Paolo Suin , Doris Arzoumanian , Annie Zavagno , Patrick Hennebelle
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