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Related papers: Dynamical HII Region Evolution in Turbulent Molecu…

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We analyze the distribution of the interstellar matter in the environs of the HII region Gum31, excited by the open cluster NGC3324, located in the complex Carina region, with the aim of investigating the action of the massive stars on the…

Astrophysics · Physics 2009-11-13 C. Cappa , V. S. Niemela , R. Amorin , J. Vasquez

Mid-infrared arcs of dust emission are often seen near ionizing stars within HII regions. A possible explanations for these arcs is that they could show the outer edges of asymmetric stellar wind bubbles. We use two-dimensional,…

We investigate turbulent gas motions in spiral galaxies and their importance to star formation in far outer disks, where the column density is typically far below the critical value for spontaneous gravitational collapse. Following the…

Astrophysics of Galaxies · Physics 2017-02-22 Erin Maier , Li-Hsin Chien , Deidre A. Hunter

Using Green Bank Telescope radio recombination line (RRL) data, we analyze the role of leaking radiation from HII regions in maintaining the ionization of the interstellar medium. We observed a sample of eight Galactic HII regions of…

Astrophysics of Galaxies · Physics 2019-02-27 Matteo Luisi , L. D. Anderson , Bin Liu , D. Anish Roshi , Ed Churchwell

It is shown that a number of key observations of the Galactic ISM can be understood, if it is treated as a highly compressible and turbulent medium energized predominantly by supernova explosions (and stellar winds). We have performed…

Astrophysics · Physics 2009-11-11 Dieter Breitschwerdt , Miguel A. de Avillez

We present a study of the filamentary structure in the atomic hydrogen (HI) emission at the 21 cm wavelength toward the Galactic plane using the observations in the HI4PI survey. Using the Hessian matrix method across radial velocity…

The nature of ultracompact H II regions (UCHRs) remains poorly determined. In particular, they are about an order of magnitude more common than would be expected if they formed around young massive stars and lasted for one dynamical time,…

Astrophysics · Physics 2009-11-11 Mordecai-Mark Mac Low , Jayashree Toraskar , Jeffrey S. Oishi , Tom Abel

The interstellar medium in star-forming galaxies is a multiphase gas in which turbulent support is at least as important as thermal pressure. Sustaining this configuration requires continuous radiative cooling, such that the overall average…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Evan Scannapieco , William J. Gray , Liubin Pan

In this contribution we present the first numerical simulations of a relativistic outflow propagating through the inner hundreds of parsecs of its host galaxy, including atomic and ionised hydrogen, and the cooling effects of ionisation.…

High Energy Astrophysical Phenomena · Physics 2022-01-05 Manel Perucho , José López-Miralles , Victoria Reynaldi , Álvaro Labiano

We used the $H\alpha$ images from a large sample of nearby late-type dwarf galaxies to investigate properties of their emission structure. The sample consists of three hundred galaxies of the irregular (Irr), Magellanic irregular (Im), blue…

Astrophysics of Galaxies · Physics 2020-12-16 Karachentsev I. D. , Kaisin S. S

Supersonic turbulence in the interstellar medium (ISM) is believed to decay rapidly within a flow crossing time irrespective of the degree of magnetization. However, this general consensus of decaying magnetohydrodynamic (MHD) turbulence…

Astrophysics of Galaxies · Physics 2013-12-10 Chang-Goo Kim , Shantanu Basu

Because of their relatively simple morphology, "bubble" HII regions have been instrumental to our understanding of star formation triggered by HII regions. With the far-infrared (FIR) spectral coverage of the Herschel satellite, we can…

We present results of numerical simulations carried out with a 2D radiation hydrodynamics code in order to study the impact of massive stars on their surrounding interstellar medium. This first paper deals with the evolution of the…

Astrophysics · Physics 2009-11-10 Tim Freyer , Gerhard Hensler , Harold W. Yorke

Using Shapefinders, which are ratios of Minkowski functionals, we study the morphology of neutral hydrogen (HI) density fields, simulated using semi-numerical technique (inside-out), at various stages of reionization. Accompanying the…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-21 Satadru Bag , Rajesh Mondal , Prakash Sarkar , Somnath Bharadwaj , Varun Sahni

Photoionization models frequently assume constant temperature or density within HII regions. We investigate this assumption by measuring the detailed temperature and density structures of four HII regions in the Large Magellanic Cloud and…

Astrophysics of Galaxies · Physics 2023-10-04 Yifei Jin , Ralph Sutherland , Lisa Kewley , David Nicholls

We present three-dimensional astrochemical simulations and synthetic observations of magnetised, turbulent, self-gravitating molecular clouds. We explore various galactic interstellar medium environments, including cosmic-ray ionization…

Astrophysics of Galaxies · Physics 2021-01-20 Thomas G. Bisbas , Jonathan C. Tan , Kei E. I. Tanaka

We model the complex distribution of atomic hydrogen (HI) in the interstellar medium (ISM) assuming that it is driven entirely by supernovae (SN). We develop and assess two different models. In the first approach, the simulated volume is…

Astrophysics · Physics 2009-11-11 Jacqueline A. Hodge , Avinash A. Deshpande

HII regions are the ionized spheres surrounding high-mass stars. They are ideal targets for tracing Galactic structure because they are predominantly found in spiral arms and have high luminosities at infrared and radio wavelengths. In the…

Astrophysics of Galaxies · Physics 2015-09-09 L. D. Anderson , L. A. Hough , T. V. Wenger , T. M. Bania , Dana S. Balser

By solving the time-dependent radiation transfer problem of stellar radiation through evolving superbubbles within a smoothly varying HI distribution, we estimate the fraction of ionizing photons emitted by OB associations that escapes the…

Astrophysics · Physics 2009-10-31 James B. Dove , J. Michael Shull , Andrea Ferrara

We use radiative transfer to study the growth of ionized regions around the brightest, z=8 quasars in a large cosmological hydrodynamic simulation that includes black hole growth and feedback (the MassiveBlack simulation). We find that in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Yu Feng , Rupert A. C. Croft , Tiziana Di Matteo , Nishikanta Khandai
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