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We investigate the effect of non-ideal magnetohydrodynamics (MHD) on the formation of binary stars using a suite of three-dimensional smoothed particle magnetohydrodynamics simulations of the gravitational collapse of one solar mass,…

Solar and Stellar Astrophysics · Physics 2016-12-08 James Wurster , Daniel J. Price , Matthew R. Bate

We model molecular cloud fragmentation with thin disk non-ideal magnetohydrodynamic simulations that include ambipolar diffusion and partial ionization that transitions from primarily ultraviolet dominated to cosmic ray dominated regimes.…

Solar and Stellar Astrophysics · Physics 2015-06-17 Nicole D. Bailey , Shantanu Basu

Simulations generally show that non-self-gravitating clouds have a lognormal column density ($\Sigma$) probability distribution function (PDF), while self-gravitating clouds with active star formation develop a distinct power-law tail at…

Astrophysics of Galaxies · Physics 2017-12-20 Sayantan Auddy , Shantanu Basu , Takahiro Kudoh

We analyze the magneto-rotational instability (MRI) effects on gravitational collapse and its influence on the instability critical scale. In particular, we study an axisymmetric nonstratified differentially rotating cloud, embedded in a…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-10 Giovanni Montani , Giovanni Palermo , Nakia Carlevaro

In two previous papers we formulated and solved, for a fiducial set of free parameters, the problem of the formation and evolution of a magnetically supercritical core inside a magnetically subcritical parent cloud. In this paper we present…

Astrophysics · Physics 2011-02-11 Konstantinos Tassis , Telemachos Ch. Mouschovias

We present self-similar solutions that describe the gravitational collapse of rotating, isothermal, magnetic molecular-cloud cores, relevant to the formation of rotationally supported protostellar disks. This work focuses on the evolution…

Astrophysics · Physics 2009-11-07 Ruben Krasnopolsky , Arieh Konigl

Star formation in our Galaxy occurs in molecular clouds that are self-gravitating, highly turbulent, and magnetized. We study the conditions under which cloud cores inherit large-scale magnetic field morphologies and how the field is…

Astrophysics of Galaxies · Physics 2017-03-29 Philip Mocz , Blakesley Burkhart , Lars Hernquist , Chris McKee , Volker Springel

Combining numerical simulations and analytical modeling, we investigate whether close binary systems form by the effect of magnetic braking. Using magnetohydrodynamics simulations, we calculate the cloud evolution with a sink, for which we…

Solar and Stellar Astrophysics · Physics 2021-10-13 Naoto Harada , Shingo Hirano , Masahiro N. Machida , Takashi Hosokawa

We study the amplification of magnetic fields in the collapse and the post-bounce evolution of the core of a non-rotating star of 15 solar masses in axisymmetry. To this end, we solve the coupled equations of magnetohydrodynamics and…

Solar and Stellar Astrophysics · Physics 2015-06-19 Martin Obergaulinger , Thomas Janka , Miguel Ángel Aloy Torás

We perform fully general relativistic simulations of rotating stellar core collapse in three spatial dimension. A parametric equation of state is adopted following Dimmelmeier et al. The early stage of the collapse is followed by an…

Astrophysics · Physics 2008-11-26 Masaru Shibata , Yu-ichirou Sekiguchi

Fragmentation process in a cylindrical magnetized cloud is studied with the nested grid method. The nested grid scheme use 15 levels of grids with different spatial resolution overlaid subsequently, which enables us to trace the evolution…

Astrophysics · Physics 2015-06-24 Kohji Tomisaka

We study the stellar bar growth in high resolution numerical galaxy models with and without dark matter halos. In all models the galactic disk is exponential and the halos are rigid or live Plummer spheres. More specifically, when there is…

Astrophysics of Galaxies · Physics 2018-02-21 Mahmood Roshan

In nearby star-forming clouds, amplification and dissipation of the magnetic field are known to play crucial roles in the star-formation process. The star-forming environment varies from place to place and era to era in galaxies. In the…

Solar and Stellar Astrophysics · Physics 2018-01-24 Koki Higuchi , Masahiro N. Machida , Hajime Susa

The configuration and evolution of the magnetic field in star-forming cores are investigated in order to directly compare simulations and observations. We prepare four different initial clouds having different magnetic field strengths and…

Solar and Stellar Astrophysics · Physics 2015-06-11 Akimasa Kataoka , Masahiro N. Machida , Kohji Tomisaka

We simulate fragmentation and gravitational collapse of cold, magnetized molecular clouds. We explore the nonlinear development of an instability mediated by ambipolar diffusion, in which the collapse rate is intermediate to fast…

Astrophysics · Physics 2009-10-31 R. Indebetouw , E. G. Zweibel

Many disc galaxies host galactic bars, which exert time-dependent, non-axisymmetric forces that can alter the orbits of stars. There should be both angle and radius-dependence in the resulting radial rearrangement of stars ('radial mixing')…

Astrophysics of Galaxies · Physics 2023-11-06 Carrie Filion , Rachel L. McClure , Martin D. Weinberg , Elena D'Onghia , Kathryne J. Daniel

We analyze the evolution of stellar bars in galactic disks in mildly triaxial flat-core and cuspy CDM halos. We use tailored simulations of rigid and live halos which include the feedback from disk/bar onto the halo in order to test the…

Astrophysics · Physics 2009-11-10 Ingo Berentzen , Isaac Shlosman , Shardha Jogee

Bars in galaxies may develop through a global instability or due to an interaction with another system. We study bar formation in disky dwarf galaxies orbiting a Milky Way-like galaxy. We employ $N$-body simulations to study the impact of…

Astrophysics of Galaxies · Physics 2017-06-28 Grzegorz Gajda , Ewa L. Lokas , E. Athanassoula

We carry out three-dimensional MHD simulations of star formation in turbulent, magnetized clouds, including ambipolar diffusion and feedback from protostellar outflows. The calculations focus on relatively diffuse clouds threaded by a…

Astrophysics · Physics 2009-11-13 Fumitaka Nakamura , Zhi-Yun Li

Collapse of the rotating magnetized molecular cloud core is studied with the axisymmetric magnetohydrodynamical (MHD) simulations. Due to the change of the equation of state of the interstellar gas, the molecular cloud cores experience…

Astrophysics · Physics 2009-11-06 Kohji Tomisaka