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In galactic disks, galactic rotation sets the bulk motion of gas, and its energy and momentum can be transferred toward small scales. Additionally, in the interstellar medium, random and noncircular motions arise from stellar feedback,…

The case of the planar circular restricted three-body problem is used as a test field in order to determine the character of the orbits of a small body which moves under the gravitational influence of the two heavy primary bodies. We…

Space Physics · Physics 2017-09-28 Euaggelos E. Zotos

We describe three-dimensional general relativistic magnetohydrodynamic simulations of a geometrically thin accretion disk around a non-spinning black hole. The disk has a thickness $h/r\sim0.05-0.1$ over the radial range $(2-20)GM/c^2$. In…

We report on the results of the first 3D SPH simulation of massive, gravitationally unstable protoplanetary disks with radiative transfer. We adopt a flux-limited diffusion scheme justified by the high opacity of most of the disk. The…

Astrophysics · Physics 2009-11-11 Lucio Mayer , Graeme Lufkin , Thomas Quinn , James Wadsley

Abridged: Recent simulations have explored different ways to form accretion disks around low-mass stars. We aim to present observables to differentiate a rotationally supported disk from an infalling rotating envelope toward deeply embedded…

Solar and Stellar Astrophysics · Physics 2015-04-29 Daniel Harsono , Ewine van Dishoeck , Simon Bruderer , Zhi-Yun Li , Jes Jorgensen

The discovery of galaxies with regularly rotating discs at redshifts $\geq$ has been a puzzling challenge to galaxy formation models that tend to predict chaotic gas kinematics in the early Universe as a consequence of gas accretion,…

Astrophysics of Galaxies · Physics 2023-03-15 Fernanda Roman-Oliveira , Filippo Fraternali , Francesca Rizzo

Molecular gas disks are generally Toomre stable ($Q_T>$1) and yet clearly gravitationally unstable to structure formation as evidenced by the existence of molecular clouds and ongoing star formation. This paper adopts a 3D perspective to…

Astrophysics of Galaxies · Physics 2022-10-12 Sharon E. Meidt

We examined the gravitational contraction of isothermal molecular cloud cores with slow rotation by means of two-dimensional numerical simulations. Applying a sink-cell method, we followed the evolution of the cloud cores up to the stages…

Astrophysics · Physics 2009-10-31 Fumitaka Nakamura

It is generally thought that protoplanetary disks embedded in envelopes are more massive and thus more susceptible to gravitational instabilities (GIs) than exposed disks. We present three-dimensional radiative hydrodynamics simulations of…

Astrophysics · Physics 2009-11-13 Kai Cai , Richard H. Durisen , Aaron C. Boley , Megan K. Pickett , Annie C. Mejia

The kinematical properties of the Galactic Thick Disk are studied using absolute proper motions from the SPM3 Catalog and 2MASS near-infrared photometry for a sample of ~1200 red giants in the direction of the South Galactic Pole. The…

In this paper, we aim to estimate the vertical gradients in the rotational velocity of the Galaxy. This is carried out in the framework of a global thin disc model approximation. The predicted gradient values coincide with the observed…

Astrophysics of Galaxies · Physics 2015-03-13 Joanna Jałocha , Łukasz Bratek , Marek Kutschera , Piotr Skindzier

Dwarf Irregular galaxies (dIrrs) are the smallest stellar systems with extended HI discs. The study of the kinematics of such discs is a powerful tool to estimate the total matter distribution at these very small scales. In this work, we…

Astrophysics of Galaxies · Physics 2017-03-22 Giuliano Iorio , Filippo Fraternali , Carlo Nipoti , Enrico Di Teodoro , Justin I. Read , Giuseppina Battaglia

We explore the properties of cold gravitoturbulent accretion disks - non-fragmenting disks hovering on the verge of gravitational instability - using a realistic prescription for the effective viscosity caused by gravitational torques. This…

Earth and Planetary Astrophysics · Physics 2009-10-02 Roman R. Rafikov

Much of standard galaxy dynamics rests on the implicit assumption that the corresponding N-body problem is (near) integrable. This notion although leading to great simplification is by no means a fact. It is therefore important to develop…

Astrophysics · Physics 2008-02-03 Amr El-Zant

In this fourth article on weighing the Galactic disk using the shape of the phase-space spiral, we have tested our method on a billion particle three-dimensional N-body simulation, comprised of a Milky Way like host galaxy and a merging…

Astrophysics of Galaxies · Physics 2022-07-06 Axel Widmark , Jason A. S. Hunt , Chervin F. P. Laporte , Giacomo Monari

We applied the currently most comprehensive version of the statistical-parallax technique to derive kinematical parameters of the maser sample with 136 sources. Our kinematic model comprises the overall rotation of the Galactic disk and the…

Astrophysics of Galaxies · Physics 2017-06-21 A. S. Rastorguev , N. D. Utkin , M. V. Zabolotskikh , A. K. Dambis , A. T. Bajkova , V. V. Bobylev

Astronomers recently discovered a non-trivial radial motion of stars within our galaxy and were able to reproduce the results using n-body numerics. I modeled a protoplanitary-like disk within a newtonian $\infty$-body problem and…

Astrophysics of Galaxies · Physics 2009-06-14 T. Hartung

In the Gaia era, understanding the effects of the perturbations of the Galactic disc is of major importance in the context of dynamical modelling. In this theoretical paper we extend previous work in which, making use of the epicyclic…

Astrophysics of Galaxies · Physics 2022-02-02 H. Al Kazwini , Q. Agobert , A. Siebert , B. Famaey , G. Monari , S. Rozier , P. Ramos , R. Ibata , S. Gausland , C. Riviere , D. Spolyar

We address the puzzling observational indications for very "cold" galactic discs at redshifts $z \gtrsim 3$, an epoch when discs are expected to be highly perturbed. Using a high-resolution cosmological zoom-in simulation, we identify such…

Astrophysics of Galaxies · Physics 2022-01-21 Michael Kretschmer , Avishai Dekel , Romain Teyssier

The migration of planetary cores embedded in a protoplanetary disk is an important mechanism within planet-formation theory, relevant for the architecture of planetary systems. Consequently, planet migration is actively discussed, yet often…

Earth and Planetary Astrophysics · Physics 2019-11-06 Philipp Weber , Sebastián Pérez , Pablo Benítez-Llambay , Oliver Gressel , Simon Casassus , Leonardo Krapp