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At least 25 per cent of massive stars are ejected from their parent cluster, becoming runaways or exiles, travelling with often-supersonic space velocities through the interstellar medium (ISM). Their overpressurised H II regions impart…

Astrophysics of Galaxies · Physics 2014-08-25 Jonathan Mackey , Norbert Langer , Vasilii V. Gvaramadze

Determining the properties of solar-like oscillating stars can be subject to many biases. A particularly important example is the helium-mass degeneracy, where the uncertainties regarding the internal physics can cause a poor determination…

Solar and Stellar Astrophysics · Physics 2021-11-24 Pierre S. Houdayer , Daniel R. Reese , Marie-Jo Goupil , Yveline Lebreton

The formation of massive stars may take place at relatively low accretion rates over a long period of time if the accretion can continue past the onset of core hydrogen ignition. The accretion may continue despite the formation of an…

Astrophysics · Physics 2009-11-10 Eric Keto

Many ultracompact HII regions exhibit a cometary morphology in radio continuum emission. In such regions, a young massive star is probably ablating, through its ultraviolet radiation, the molecular cloud clump that spawned it. On one side…

Astrophysics of Galaxies · Physics 2015-06-18 Nathaniel Roth , Steven W. Stahler , Eric Keto

We demonstrate that the resolution of three-dimensional (3D) real-space images obtained from Bragg x-ray coherent diffraction measurements is direction dependent. We propose and demonstrate the effectiveness of a metric to determine the…

Optics · Physics 2018-12-13 Mathew J. Cherukara , Wonsuk Cha , Ross J. Harder

Context. Understanding the conditions in which stars and stellar clusters form is of great importance. In particular the role that stellar feedback may have is still hampered by large uncertainties. Aims. We investigate the role played by…

Astrophysics of Galaxies · Physics 2022-07-20 Antoine Verliat , Patrick Hennebelle , Marta González , Yueh-Ning Lee , Sam Geen

Interarm star formation contributes significantly to a galaxy's star formation budget, and provides an opportunity to study stellar birthplaces unperturbed by spiral arm dynamics. Using optical integral field spectroscopy of the nearby…

Astrophysics of Galaxies · Physics 2016-08-17 K. Kreckel , G. A. Blanc , E. Schinnerer , B. Groves , A. Adamo , A. Hughes , S. Meidt

We use the full-disk VLT-MUSE mosaic of NGC 253 to identify 2492 HII regions and study their resolved structure. With an average physical resolution of 17 pc, this is one of the largest samples of highly resolved spectrally mapped…

Context: How do expanding HII regions interact with their environmental cloud? This is one of the central questions driving the SOFIA legacy program FEEDBACK. Here, we present a case study toward the prototypical H{\sc ii} region NGC7538.…

The generation of infrared (IR) radiation and the observed IR intensity distribution at wavelengths of 8, 24, and 100 micron in the ionized hydrogen region around a young, massive star is investigated. The evolution of the HII region is…

Astrophysics of Galaxies · Physics 2015-06-16 Yaroslav Pavlyuchenkov , Maria Kirsanova , Dmitry Wiebe

We investigate the relationship of the HII region luminosity function (HII LF) to the HII region size distribution and density wave triggering in grand-design spiral galaxies. We suggest that the differential nebular size distribution is…

Astrophysics · Physics 2009-11-10 M. S. Oey , J. S. Parker , V. J. Mikles , X. Zhang

A number of very small isolated HII regions have been discovered at projected distances up to 30 kpc from their nearest galaxy. These HII regions appear as tiny emission line objects in narrow band images obtained by the NOAO Survey for…

In this work, we explore the impact of higher dimensional spacetime on the stellar structure and thermodynamic properties of neutron stars. Utilizing the density-dependent relativistic hadron field theory, we introduce modifications to…

General Relativity and Quantum Cosmology · Physics 2024-03-13 Debabrata Deb , Manjari Bagchi , Sarmistha Banik

The spatial distribution of metals reflects, and can be used to constrain, the processes of chemical enrichment and mixing. Using PHANGS-MUSE optical integral field spectroscopy, we measure the gas phase oxygen abundances (metallicities)…

The spiral structure of the Milky Way is not conclusive, even for the disc regions in the solar neighbourhood. Especially, the arm-like structures uncovered from the over-density maps of evolved stars are inconsistent with the commonly…

Astrophysics of Galaxies · Physics 2025-04-09 X. J. Shen , L. G. Hou , H. L. Liu , X. Y. Gao

Stellar feedback in dwarf galaxies remains, to date, poorly explored, yet is crucial to understanding galaxy evolution in the early Universe. In particular, pre-supernova feedback has recently been found to play a significant role in…

We analyze the statistical properties of the circumnuclear HII regions of a sample of 52 nearby galaxies ($v < 1000km/s) from archival HST/NICMOS H-band and Pa alpha (1.87micron) observations at unprecedented spatial resolutions of between…

Astrophysics · Physics 2009-11-06 Almudena Alonso-Herrero , Johan H. Knapen

The study is devoted to comparing the parameters of the interstellar medium of HII regions in the Kongiu and Groves catalogs for the galaxy NGC 628. The article analyzes the characteristics of star-forming regions, including a comparison of…

Astrophysics of Galaxies · Physics 2026-01-16 Ksenia I. Smirnova , Dmitri S. Wiebe

We present results from photoionization models of low-metallicity HII regions. These nebulae form the basis for measuring the primordial helium abundance. Our models show that the helium ionization correction factor (ICF) can be…

Astrophysics · Physics 2009-10-31 D. R. Ballantyne , G. J. Ferland , P. G. Martin

We study the structural evolution of turbulent molecular clouds under the influence of ionizing radiation emitted from a nearby massive star by performing a high resolution parameter study with the iVINE code. The temperature is taken to be…

Solar and Stellar Astrophysics · Physics 2015-05-19 Matthias Gritschneder , Andreas Burkert , Thorsten Naab , Stefanie Walch