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Related papers: Inverse Hubble Flows in Molecular Clouds

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In the Galactic fountain scenario, supernovae and/or stellar winds propel material into the Galactic halo. As the material cools, it condenses into clouds. By using FLASH three-dimensional magnetohydrodynamic simulations, we model and study…

Astrophysics of Galaxies · Physics 2014-11-20 Kyujin Kwak , Robin L. Shelton , Elizabeth A. Raley

We study the observable signatures of self-gravitating MHD turbulence by applying the probability density functions (PDFs) and the spatial density power spectrum to synthetic column density maps. We find that there exists three…

Solar and Stellar Astrophysics · Physics 2015-08-06 Blakesley Burkhart , David C. Collins , Alex Lazarian

We show that the "cold" Hubble flow observed for galaxies around the Milky Way does not represent a problem in cosmology but is due to the particular geometry and dynamics of our local wall. The behavior of the perturbed Hubble flow around…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 M. A. Aragon-Calvo , J. Silk , A. S. Szalay

We investigate the evolution of matter density perturbations within a fractional cosmological framework inspired by fractal space-time constructions in field theory, where a deformation of the integration measure induces non-locality and…

General Relativity and Quantum Cosmology · Physics 2026-04-24 S. M. M. Rasouli

This study is motivated by recent observations on ubiquitous interstellar density filaments and guided by modern theories of compressible magnetohydrodynamic (MHD) turbulence. The interstellar turbulence shapes the observed density…

Astrophysics of Galaxies · Physics 2019-08-07 Siyao Xu , Suoqing Ji , A. Lazarian

We compile a holistic scenario for molecular cloud (MC) evolution and control of the star formation efficiency (SFE), and present a first set of numerical tests of it. A {\it lossy} compressible cascade can generate density fluctuations and…

Astrophysics · Physics 2009-11-07 E. Vazquez-Semadeni , J. Ballesteros-Paredes , R. S. Klessen

We discuss the mechanism of cluster formation in hierarchically collapsing molecular clouds. Recent evidence, both observational and numerical, suggests that molecular clouds (MCs) may be undergoing global, hierarchical gravitational…

Astrophysics of Galaxies · Physics 2017-04-05 Enrique Vazquez-Semadeni , Alejandro Gonzalez-Samaniego , Manuel Zamora-Aviles , Pedro Colin

We present three numerical simulations of randomly driven, isothermal, non-magnetic, self-gravitating turbulence with different rms Mach numbers Ms and physical sizes L, but approximately the same value of the virial parameter, alpha approx…

We decomposed the G333 complex and the G331 giant molecular cloud into multi-scale hub-filament systems (HFs) using the high-resolution $^{13}$CO (3$-$2) data from LAsMA observations. We employed the filfinder algorithm to identify and…

Astrophysics of Galaxies · Physics 2025-06-23 J. W. Zhou , J. S. Urquhart , F. Wyrowski , S. Neupane , T. Liu , M. Juvela

We present radiation-magnetohydrodynamic simulations aimed at studying evolutionary properties of H\,{\normalsize II} regions in turbulent, magnetised, and collapsing molecular clouds formed by converging flows in the warm neutral medium.…

When a self-gravitating spherical gas cloud collapses or accretes onto a central mass, the inner region of the cloud develops a density profile $\rho\propto r^{-3/2}$ and the velocity approaches free-fall. We show that in this region,…

Astrophysics · Physics 2009-10-31 Dong Lai , Peter Goldreich

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

A stochastic model of fragmentation of molecular clouds has been developed for studying the resulting Initial Mass Function (IMF) where the number of fragments, inter-occurrence time of fragmentation, masses and velocities of the fragments…

Astrophysics of Galaxies · Physics 2020-06-11 Suman Paul , Tanuka Chattopadhyay

We study the linear evolution of small perturbations in self-gravitating fluid systems with magnetic fields. We consider wave-like perturbations to nonuniform filamentary and sheet-like hydrostatic equilibria in the presence of a uniform…

Astrophysics · Physics 2015-06-24 Curtis S. Gehman , Fred C. Adams , Richard Watkins

In the context of star formation through fragmentation of an extremely metal-deficient protogalactic cloud, the gravitational collapse of filamentary gas clouds is explored with 1D numerical hydrodynamics coupled with non-equilibrium…

Astrophysics · Physics 2009-11-07 Fumitaka Nakamura , Masayuki Umemura

We discuss the effect of super-Hubble cosmological fluctuations on the locally measured Hubble expansion rate. We consider a large bare cosmological constant in the early universe in the presence of scalar field matter (the dominant matter…

High Energy Physics - Theory · Physics 2018-11-28 Robert Brandenberger , Leila L. Graef , Giovanni Marozzi , Gian Paolo Vacca

We present a numerical investigation of the evolution of the Hawking mass for perturbed surfaces evolving under hypersurface-restricted uniformly expanding flows in Minkowski spacetime. Although monotonicity of the Hawking mass under…

General Relativity and Quantum Cosmology · Physics 2026-05-26 Hollis Williams

We discuss the mechanism of cluster formation in a numerical simulation of a molecular cloud (MC) undergoing global hierarchical collapse (GHC). The global nature of the collapse implies that the SFR increases over time. The hierarchical…

Astrophysics of Galaxies · Physics 2017-04-19 Enrique Vazquez-Semadeni , Alejandro Gonzalez-Samaniego , Pedro Colin

In the early Universe, large-scale flows were omnipresent, and the flow collisions produced sheets and filaments. This phenomenon occurs for both particle and wave dark matter. But for the latter, these sheets and filaments are the…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-20 Ui-Han Zhang , Tak-Pong Woo , Tzihong Chiueh

In order to understand the origin of observed molecular cloud properties, it is critical to understand how clouds interact with their environments during their formation, growth, and collapse. It has been suggested that accretion-driven…

Astrophysics of Galaxies · Physics 2018-12-21 Juan C. Ibáñez-Mejía , Mordecai-Mark Mac Low , Ralf S. Klessen , Christian Baczynski