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Related papers: Thermal Instability behind a Shock Wave in HI and …

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An overview is presented of the main properties of the interstellar medium. Evidence is summarized that the interstellar medium is highly turbulent, driven on different length scales by various energetic processes. Large-scale turbulence…

Astrophysics · Physics 2009-11-11 Andreas Burkert

We investigate the properties of highly compressible turbulence, the compressibility arising from a small effective polytropic exponent $\gamma_e$ due to cooling. In the limit of small $\gamma_e$, the density jump at shocks is shown to be…

Astrophysics · Physics 2009-10-28 E. Vazquez-Semadeni , T. Passot , A. Pouquet

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

Within a few parsecs around the central Black Hole Sgr A*, chemistry in the dense molecular cloud material of the circumnuclear disk (CND) can be affected by many energetic phenomena such as high UV-flux from the massive central star…

We investigate the evolution of molecular clouds through the kinematics of their atomic hydrogen (HI) envelopes, using $^{12}\mathrm{CO}$ and 21-cm emission to trace the molecular and atomic gas, respectively. We measure the large-scale…

Astrophysics of Galaxies · Physics 2026-02-03 Thummim Mekuria , Nia Imara

Heat input roughly balances radiative cooling in the gaseous cores of galaxy clusters even when the central cooling time is short, implying that cooling triggers a feedback loop that maintains thermal balance. Furthermore, cores with short…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-06 Gregory Meece , Brian O'Shea , Mark Voit

We investigate the thermodynamics of the ISM and the formation of molecular hydrogen through numerical simulations of spiral galaxies. The model follows the chemical, thermal and dynamical response of the disc to an external spiral…

Astrophysics · Physics 2009-11-13 Clare Dobbs , Simon Glover , Paul Clark , Ralf Klessen

The formation of molecular clouds out of HI gas is the first step toward star formation. Its metallicity dependence plays a key role to determine star formation through the cosmic history. Previous theoretical studies with detailed chemical…

Astrophysics of Galaxies · Physics 2023-08-29 Masato I. N. Kobayashi , Kazunari Iwasaki , Kengo Tomida , Tsuyoshi Inoue , Kazuyuki Omukai , Kazuki Tokuda

We study thermal-gravitational instability in simplified models for protogalactic halos using three-dimensional hydrodynamic simulations. The simulations followed the evolution of gas with radiative cooling down to T = 10^4 K, background…

Astrophysics · Physics 2009-11-11 Chang Hyun Baek , Hyesung Kang , Jongsoo Kim , Dongsu Ryu

We study the stability properties of hydrodynamic shocks with finite Mach numbers. The linear analysis supplements previous analyses which took the strong shock limit. We derive the linearised equations for a general specific heat ratio as…

Astrophysics · Physics 2009-11-13 Babulakshmanan Ramachandran , Michael D. Smith

Thermal instability is one of the most important processes in the formation of clumpy substructure in magnetic molecular clouds. On the other hand, ambipolar diffusion, or ion-neutral friction, has long been thought to be an important…

Astrophysics · Physics 2009-11-10 Mohsen Nejad-Asghar , Jamshid Ghanbari

We study the properties of cosmological shock waves identified in high-resolution, N-body/hydrodynamic simulations of a $\Lambda$CDM universe and their role on thermalization of gas and acceleration of nonthermal, cosmic ray (CR) particles.…

Astrophysics · Physics 2008-11-26 Dongsu Ryu , Hyesung Kang , Eric Hallman , T. W. Jones

We simulate the multi-phase interstellar medium randomly heated and stirred by supernovae, with gravity, differential rotation and other parameters of the solar neighbourhood. Here we describe in detail both numerical and physical aspects…

Astrophysics of Galaxies · Physics 2013-04-03 F. A. Gent , A. Shukurov , A. Fletcher , G. R. Sarson , M. J. Mantere

We study the formation of giant dense cloud complexes and of stars within them by means of SPH numerical simulations of the mildly supersonic collision of gas streams (``inflows'') in the warm neutral medium (WNM). The resulting…

We examine the thermodynamic state and cooling of the low-$z$ Circum-Galactic Medium (CGM) in five FIRE-2 galaxy formation simulations of Milky Way-mass galaxies. We find that the CGM in these simulations is generally multiphase and…

We describe our modelling of the radiatively cooling shocks and their thin shells with various numerical tools in different physical and calculational setups. We inspect structure of the dense shell, its formation and evolution, pointing…

High Energy Astrophysical Phenomena · Physics 2016-05-05 D. A. Badjin , S. I. Glazyrin , K. V. Manukovskiy , S. I. Blinnikov

Observational evidence shows that low-redshift galaxies are surrounded by extended haloes of multiphase gas, the so-called 'circumgalactic medium' (CGM). To study the survival of relatively cool gas (T < 10^5 K) in the CGM, we performed a…

Astrophysics of Galaxies · Physics 2017-06-28 L. Armillotta , F. Fraternali , J. K. Werk , J. X. Prochaska , F. Marinacci

(Abridged) We discuss the nonlinear development of the isobaric mode of thermal instability (TI) in the context of the atomic interstellar medium (ISM), in order to assess the ability of TI to establish a well-segregated multi-phase…

Astrophysics · Physics 2009-11-07 F. J. Sanchez-Salcedo , E. Vazquez-Semadeni , A. Gazol

We have modeled the gas temperature structure in unstable C-type shocks and obtained predictions for the resultant CO and H2 rotational line emissions, using numerical simulations of the Wardle instability that were carried out by Stone…

Astrophysics · Physics 2009-10-30 David A. Neufeld , James M. Stone

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