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Related papers: Expansive components in H II regions

200 papers

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 a systematic survey of multiple velocity-resolved H$_2$O spectra using Herschel/HIFI towards nine nearby actively star forming galaxies. The ground-state and low-excitation lines (E$_{\rm up}\,\le 130\,{\rm K}$) show profiles…

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.…

It has been shown that by means of different physical mechanisms the expansion of HII regions can trigger the formation of new stars of all masses. This process may be important to the formation of massive stars but has never been…

We investigate the star formation activity in the molecular complex associated with the Galactic HII region Sh2-90, using radio-continuum maps obtained at 1280 MHz and 610 MHz, Herschel Hi-GAL observations at 70 -- 500 microns, and deep…

Solar and Stellar Astrophysics · Physics 2015-06-19 M. R. Samal , A. Zavagno , L. Deharveng , S. Molinari , D. K. Ojha , D. Paradis , J. Tigé , A. K. Pandey , D. Russeil

Plasma outflows from the edges of active regions have been suggested as a possible source of the slow solar wind. Spectroscopic measurements show that these outflows have an enhanced elemental composition, which is a distinct signature of…

We present Chandra X-ray images for the interacting galaxy pair NGC 7714/5. In addition to the unresolved starburst nucleus, a variable point source with L(X) ~ 10^40 erg/s was detected 1.5" (270 pc) northwest of the nucleus, coincident…

Astrophysics · Physics 2009-11-10 Beverly J. Smith , Curtis Struck , Michael A. Nowak

We present the measurements of gas and stellar velocity dispersions in 17 circumnuclear star-forming regions (CNSFRs) and the nuclei of three barred spiral galaxies: NGC2903, NGC3310 and NGC3351 from high dispersion spectra. The stellar…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-17 G. F. Hagele , M. V. Cardaci , G. L. Bosch , A. I. Diaz , E. Terlevich , R. Terlevich

Radiation pressure acting on gas and dust causes HII regions to have central densities that are lower than the density near the ionized boundary. HII regions in static equilibrium comprise a family of similarity solutions, parametrized by 3…

Astrophysics of Galaxies · Physics 2015-05-18 B. T. Draine

The conversion of the IR emission into star formation rate can be strongly dependent on the physical properties of the dust, which are affected by the environmental conditions where the dust is embedded. We study here the dust properties of…

Actively accreting supermassive black holes significantly impact the evolution of their host galaxies, truncating further star formation by expelling large fractions of gas with wide-angle outflows. The X-ray band is key to understanding…

High Energy Astrophysical Phenomena · Physics 2022-10-05 A. Ogorzalek , A. L. King , S. W. Allen , J. C. Raymond , D. R. Wilkins

Photodissociated gas bears the signature of the dynamical evolution of the ambient interstellar medium impacted by the mechanical and radiative feedback from an expanding HII region. Here we present an analysis of the kinematics of the…

Astrophysics of Galaxies · Physics 2024-01-04 Bhaswati Mookerjea , Goeran Sandell

We present a multiwavelength (ultraviolet, infrared, optical and CO) study of a set of luminous HII regions in M33: NGC 604, NGC 595, NGC 592, NGC 588 and IC131. We study the emission distribution in the interiors of the HII regions to…

Astrophysics of Galaxies · Physics 2011-02-11 Monica Relano , Robert C. Kennicutt

The presence of broad wings in the H$\alpha$ line is commonly used as a diagnostic of the presence and properties of galactic winds from star-forming galaxies. However, the accuracy of this approach has not been subjected to extensive…

Astrophysics of Galaxies · Physics 2026-05-29 Rongjun Huang , Aditi Vijayan , Mark R. Krumholz

Context. Ionization plays a central role in the gas-phase chemistry of molecular clouds. Since ions are coupled with magnetic fields, which can in turn counteract gravitational collapse, it is of paramount importance to measure their…

Astrophysics of Galaxies · Physics 2014-03-21 J. L. Morales Ortiz , C. Ceccarelli , D. C. Lis , L. Olmi , R. Plume , P. Schilke

We present a study of the extinction, traced by the Balmer decrement, in HII regions in the dwarf galaxies NGC 1569 and NGC 4214. We find that the large-scale extinction around the most prominent HII regions in both galaxies forms a shell…

Astrophysics · Physics 2009-11-13 U. Lisenfeld , M. Relano , J. Vilchez , E. Battaner , I. Hermelo

The nebular properties (electronic density, extinction, age, O/H abundances) of HII regions found along the bars of the sample of barred spiral galaxies studied by Martin & Friedli (1997) are examined. From line ratio diagnostic diagrams,…

Astrophysics · Physics 2007-05-23 P. Martin , D. Friedli

We present a pilot survey of 21 lines of sight towards UCHII regions in the H2CO 1-1 (6cm) and 2-2 (2cm) transitions, using the H2CO centimeter lines as a molecular gas densitometer. Using Arecibo and Green Bank beam-matched observations,…

Astrophysics of Galaxies · Physics 2011-07-27 Adam Ginsburg , Jeremy Darling , Cara Battersby , Ben Zeiger , John Bally

One of the fundamental factors regulating the evolution of galaxies is stellar feedback. However, we still do not have strong observational constraints on the relative importance of the different feedback mechanisms (e.g. radiation, ionised…

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