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Spherical flows are a classic problem in astrophysics which are typically studied from a global perspective. However, much like with accretion discs, there are likely many instabilities and small scale phenomena which would be easier to…

Astrophysics of Galaxies · Physics 2023-08-02 Elliot M. Lynch , Guillaume Laibe

Using the PMO-13.7 m millimeter telescope at Delingha in China, we have conducted a large-scale simultaneous survey of $^{12}$CO, $^{13}$CO, and C$^{18}$O $J=1-0$ emission toward the sky region centered at $l$=$209.7^\circ$,…

Astrophysics of Galaxies · Physics 2020-09-15 Chong Li , Hongchi Wang , Miaomiao Zhang , Yuehui Ma , Lianghao Lin

We propose a novel mathematical method to construct an exact polytropic sphere in self-gravitating hydrostatic equilibrium, improving the non-linear Poisson equation. The central boundary condition for the present equation requires a ratio…

Astrophysics · Physics 2009-11-07 Mitsuru Honda , Yasuko. S. Honda

We derive self-similar solutions including cooling and heating in an Einstein de-Sitter universe, and investigate the effects of cooling and heating on the gas density and temperature distributions. We assume that the cooling rate has a…

Astrophysics · Physics 2009-11-10 Shuji Uchida , Tatsuo Yoshida

We present 3D "zoom-in" simulations of the formation of two molecular clouds out of the galactic interstellar medium. We model the clouds - identified from the SILCC simulations - with a resolution of up to 0.06 pc using adaptive mesh…

Astrophysics of Galaxies · Physics 2017-10-18 D. Seifried , S. Walch , P. Girichidis , T. Naab , R. Wünsch , R. S. Klessen , S. C. O. Glover , T. Peters , P. Clark

The origin of rovibrational H_2 emission in the central galaxies of cooling flow clusters is poorly understood. Here we address this issue using data from our near-infrared spectroscopic survey of 32 of the most line luminous such systems,…

Astrophysics · Physics 2009-09-17 R. J. Wilman , A. C. Edge , R. M. Johnstone , A. C. Fabian , S. W. Allen , C. S. Crawford

The classical problem of spherical homologous gravitational collapse with a polytropic equation of state for pressure is examined in Lagrangian fluid coordinate, where the position of each initial fluid element {\eta} = r(0) is followed in…

Astrophysics of Galaxies · Physics 2015-06-25 KH Tsui , CE Navia

The variation of an ionizing flux as a mechanism to stimulate the condensation of a diffuse gas is considered. To illustrate this effect, two situations are examined: one on the context of pregalactic conditions, and the other on the…

Astrophysics · Physics 2007-05-23 Antonio Parravano , Catherine Pech

We consider a strong ultrarelativistic shock moving through a star whose envelope has a polytrope-like density profile. When the shock is close to the star's outer boundary, its behavior follows the self-similar solution given by Sari…

Astrophysics · Physics 2009-11-11 Margaret Pan , Re'em Sari

Multi-dimensional fluid flow plays a paramount role in the explosions of massive stars as core-collapse supernovae. In recent years, three-dimensional (3D) simulations of these phenomena have matured significantly. Considerable progress has…

Solar and Stellar Astrophysics · Physics 2020-06-11 B. Müller

We extend recent numerical results (Dobbs et. al. 2006) on molecular cloud formation in spiral galaxies by including a multi-phase medium. The addition of a hot phase of gas enhances the structure in the cold gas, and significantly…

Astrophysics · Physics 2018-05-02 Clare Dobbs , Ian Bonnell

I model the multi-phase interstellar medium (ISM) randomly heated and shocked by supernovae, with gravity, differential rotation and other parameters we understand to be typical of the solar neighbourhood. The simulations are 3D extending…

Astrophysics of Galaxies · Physics 2017-12-15 Frederick Gent

The viscosity of supercooled liquids notably increases with decreasing temperature, leading to solidification through a glass transition. This process is accompanied by dynamic heterogeneity, characterized by persistent dynamic spatial…

Soft Condensed Matter · Physics 2024-09-30 Kento Maeda , Atsushi Ikeda

We compare the results of two techniques used to calculate the evolution of cooling gas during galaxy formation: Smooth Particle Hydrodynamics (SPH) simulations and semi-analytic modelling. We improve upon the earlier statistical comparison…

We map for the first time the two-dimensional H_2 excitation of warm intergalactic gas in Stephan's Quintet on group-wide (50 x 35 kpc^2) scales to quantify the temperature, mass and warm-H_2 mass fraction as a function of position using…

Astrophysics of Galaxies · Physics 2017-02-15 P. N. Appleton , P. Guillard , A. Togi , K. Alatalo , F. Boulanger , M. Cluver , G. Pineau des Forets , U. Lisenfeld , P. Ogle , C. K. Xu

Shocks form the basis of our understanding for the density and velocity statistics of supersonic turbulent flows, such as those found in the cool interstellar medium (ISM). The variance of the density field, $\sigma^2_{\rho/\rho_0}$, is of…

Astrophysics of Galaxies · Physics 2021-04-28 James R. Beattie , Philip Mocz , Christoph Federrath , Ralf S. Klessen

The origin of the dense gas cloud G2 discovered in the Galactic Center (Gillessen et al. 2012) is still a debated puzzle. G2 might be a diffuse cloud or the result of an outflow from an invisible star embedded in it. We present…

Astrophysics of Galaxies · Physics 2015-06-16 A. Ballone , M. Schartmann , A. Burkert , S. Gillessen , R. Genzel , T. K. Fritz , F. Eisenhauer , O. Pfuhl , T. Ott

We study dynamical condensation process in a holographic superconductor model with anisotropy. The time-dependent numerical solution is constructed for the Einstein-Maxwell-dilaton theory with complex scalar in asymptotic AdS spacetime. The…

High Energy Physics - Theory · Physics 2014-09-17 Xiaojian Bai , Bum-Hoon Lee , Miok Park , Khimphun Sunly

We study the nature of phase transitions in a self-gravitating classical gas in the presence of a central body. The central body can mimic a black hole at the center of a galaxy or a rocky core (protoplanet) in the context of planetary…

Statistical Mechanics · Physics 2023-08-08 P. H. Chavanis , J. Sopik , C. Sire

We study by Molecular Dynamics simulation the slowing down of particle motion in a two-dimensional monatomic model: a Lennard-Jones liquid on the hyperbolic plane. The negative curvature of the embedding space frustrates the long-range…

Statistical Mechanics · Physics 2008-12-19 Francois Sausset , Gilles Tarjus