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We use the three-dimensional Athena ionizing radiation-magnetohydrodynamics (IRMHD) code to simulate blister-type HII regions driven by stars on the edge of magnetized gas clouds. We compare these to simulations of spherical HII regions…

Astrophysics of Galaxies · Physics 2015-05-30 Leo Gendelev , Mark R. Krumholz

We explore to what extent simple algebraic models can be used to describe H II regions when winds, radiation pressure, gravity and photon breakout are included. We a) develop algebraic models to describe the expansion of photoionised H II…

Astrophysics of Galaxies · Physics 2020-01-08 Sam Geen , Eric Pellegrini , Rebekka Bieri , Ralf Klessen

Mapping stars and gas in nearby galaxies is fundamental for understanding their growth and the impact of their environment. This issue is addressed by comparing the stellar "edges" of galaxies $D_{\rm stellar}$, defined as the outermost…

Extensive photoionization model grids are computed for single star HII regions using stellar atmosphere models from the WM-basic code. Mid-IR emission line intensities are predicted and diagnostic diagrams of [NeIII]/[NeII] and [SIV]/[SIII]…

Astrophysics · Physics 2009-11-10 C. Morisset

Observations of infrared fine-structure lines provide direct information on the metallicity and ionization structure of HII regions and indirectly on the hardness of the radiation field ionizing these nebulae. We have analyzed a sample of…

The current state-of-the-art of multi-wavelength diagnostic tools (evolutionary synthesis, photoionisation models) for massive star forming regions (HII regions, starbursts, etc.) and some of their input physics (especially model…

Astrophysics · Physics 2007-05-23 Daniel Schaerer

We assess the impact of inhomogeneous reionization on detection of HII regions surrounding luminous high redshift quasars using planned low frequency radio telescopes. Our approach is to implement a semi-numerical scheme to calculate the…

Astrophysics · Physics 2017-07-24 Paul M. Geil , Stuart Wyithe

RHII and starbursts are both powered by massive stars. They are the main contributors to the heating of the ISM via radiative and mechanical energy. Techniques to derive the stellar content and the evolutionary state of RHIIs and starbursts…

Astrophysics · Physics 2009-10-31 Rosa M. Gonzalez Delgado

The fact that infrared ring nebulae (IRRNs) are frequently associated with HII regions, provides us the opportunity to study dust at the interface between ionized and neutral gas. In this paper, we analyze the infrared radiation in the…

Astrophysics of Galaxies · Physics 2019-11-06 A. P. Topchieva , V. V. Akimkin , G. V. Smirnov-Pinchukov

We study pre-supernova feedback in a sample of $\sim$ 4700 HII regions in the nearby spiral galaxy M83, identified on their H$\alpha$ emission. We pectroscopically identify Wolf-Rayet (WR) stars populating the star-forming regions. For each…

The location of HII regions, which indicates the locus of present star formation in galaxies, is analyzed for a large collection of 110 irregular galaxies (Irr) imaged in H$\alpha$ and nearby continuum. The analysis is primarily by visual…

Astrophysics · Physics 2015-06-24 Noah Brosch , Ana Heller , Elchanan Almoznino

This chapter reviews progress in the field of massive star formation. It focuses on evidence for accretion and current models that invoke high accretion rates. In particular it is noted that high accretion rates will cause the massive young…

Astrophysics · Physics 2016-01-27 Melvin G. Hoare , Jose Franco

Newly formed stars have a profound impact on their environment by depositing energy and momentum into the surrounding gas. However, only a fraction of the stellar feedback is retained in the cloud and observational constraints are needed to…

We present in here the exploration of the physical properties of the sample of HII regions and aggregations of the last HII regions catalog of the CALIFA survey. This sample comprises the optical spectroscopic properties of more than…

Extensive photoionization model grids for single star HII regions using a variety of recent state-of-the-art stellar atmosphere models have been computed with the main aim of constraining/testing their predicted ionizing spectra against…

Astrophysics · Physics 2009-11-10 C. Morisset , D. Schaerer , J. -C. Bouret , F. Martins

The relation between the star formation rate and the kinetic energy increase in a region containing a large number of stellar sources is investigated as a possible prescription for star formation feedback in larger scale galaxy evolution…

Astrophysics · Physics 2009-10-31 John Scalo , David Chappell

Velocity shifts and differential broadening of radio recombination lines are used to estimate the densities and velocities of the ionized gas in several hypercompact and ultracompact HII regions. These small HII regions are thought to be at…

Astrophysics · Physics 2009-11-13 Eric Keto , Qizhou Zhang , Stanley Kurtz

Massive stars and their associated ionized (HII) regions could play a key role in the formation and evolution of filaments that host star formation. However, the properties of filaments that interact with H regions are still poorly known.…

Massive stars provide feedback that shapes the interstellar medium of galaxies at all redshifts and their resulting stellar populations. Here we present three adaptive mesh refinement radiation hydrodynamics simulations that illustrate the…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-13 John H. Wise , Tom Abel , Matthew J. Turk , Michael L. Norman , Britton D. Smith

By using the Hectospec 6.5 m Multiple Mirror Telescope (MMT) and the 2.16 m telescope of National Astronomical Observatories, Chinese Academy of Sciences (NAOC), we obtained 188 high signal-to-noise ratio (S/N) spectra of HII regions in the…

Astrophysics of Galaxies · Physics 2018-03-21 Ning Hu , Enci Wang , Zesen Lin , Xu Kong , Fuzhen Cheng , Zou Fan , Guanwen Fang , Lin Lin , Yewei Mao , Jing Wang , Xu Zhou , Zhiming Zhou , Yinan Zhu , Hu Zou
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