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Related papers: Expansion Signatures in 35 HII Regions traced by S…

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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 use the Mopra radio telescope to test for expansion of the molecular gas associated with the bubble HII region RCW120. A ring, or bubble, morphology is common for Galactic HII regions, but the three-dimensional geometry of such objects…

Astrophysics of Galaxies · Physics 2015-06-23 L. D. Anderson , L. Deharveng , A. Zavagno , P. Tremblin , V. Lowe , M. R. Cunningham , P. Jones , A. M. Mullins , M. P. Redman

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 expansion of Galactic HII regions can trigger the formation of a new generation of stars. However, little is know about the physical conditions that prevail in these regions. We study the physical conditions that prevail in specific…

Astrophysics of Galaxies · Physics 2015-06-24 J. A. Rodón , A. Zavagno , J. -P. Baluteau , E. Habart , M. Köhler , J. Le Bourlot , F. Le Petit , A. Abergel

The star-forming activity in the HII region RCW 42 is investigated using multiple wavebands, from near-infrared to radio wavelengths. Located at a distance of 5.8 kpc, this southern region has a bolometric luminosity of 1.8 $\times$ 10$^6$…

Astrophysics of Galaxies · Physics 2022-08-17 Vipin Kumar , S. Vig , V. S. Veena , S. Mohan , S. K. Ghosh , A. Tej , D. K. Ojha

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

We present the results of radiation-magnetohydrodynamic simulations of the expansion of HII regions and surrounding photodissociation regions in turbulent, magnetised, molecular clouds on scales of up to 4 parsecs, including the effects of…

Astrophysics of Galaxies · Physics 2015-05-27 S. J. Arthur , W. J. Henney , G. Mellema , F. De Colle , E. Vázquez-Semadeni

We studied the radio properties of very young massive regions of star formation in HII galaxies, with the aim of detecting episodes of recent star formation in an early phase of evolution where the first supernovae start to appear. Our…

Astrophysics · Physics 2008-11-26 D. Rosa-Gonzalez , H. R. Schmitt , E. Terlevich , R. Terlevich

We build, as far as theory will permit, self consistent model HII regions around central clusters of aging stars. These produce strong emission line diagnostics applicable to either individual HII regions in galaxies, or to the integrated…

We present a study of the dust properties of 12 classical and superbubble HII regions in the Large Magellanic Cloud. We use infrared photometry from Spitzer (8, 24, 70, and 160 \mum bands), obtained as part of the Surveying the Agents of a…

High-mass stars form in much richer environments than those associated with isolated low-mass stars, and once they reach a certain mass, produce ionised (HII) regions. The formation of these pockets of ionised gas are unique to the…

We present numerical radiation-hydrodynamic simulations of the evolution of HII regions formed in an inhomogeneous medium resulting from turbulence simulations. We find that the filamentary structure of the underlying density distribution…

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 have investigated 25 H II regions with bubble morphology in 13CO(1-0) and infrared data, to search the quantitative evidence for the triggering star formation by collect and collapse (CC) and radiatively driven implosion (RDI) models.…

Solar and Stellar Astrophysics · Physics 2015-06-17 Jin-Long Xu , Jun-Jie Wang , Chang-Chun Ning , Chuan-peng Zhang

Using data from the Green Bank Telescope, we analyze the radio continuum (free-free) and radio recombination line (RRL) emission of the compact HII region NGC 7538 (Sharpless 158). We detect extended radio continuum and hydrogen RRL…

Astrophysics of Galaxies · Physics 2016-06-29 Matteo Luisi , L. D. Anderson , Dana S. Balser , T. M. Bania , Trey V. Wenger

We present study of a typical explosive event (EE) at sub-arcsecond scale witnessed by strong non-Gaussian profiles with blue- and red-shifted emission of up to 150 km/s seen in the transition-region Si IV 1402.8 \AA, and the chromospheric…

Solar and Stellar Astrophysics · Physics 2015-06-23 Zhenghua Huang , Maria S. Madjarska , Lidong Xia , J. G. Doyle , Klaus Galsgaard , Hui Fu

The size-velocity dispersion ($\sigma$) relation, while well established for giant HII regions, remains uncertain for their smaller counterparts (physical radii R < 20 pc). Thanks to the LAMOST MRS-N dataset's large sky coverage and high…

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

The aim of the present work is to study structure and gas kinematics in the photodissociation regions (PDRs) around the compact HII regions S235A and S235C. We observe the [CII], [13CII] and [OI] line emission, using SOFIA/upGREAT and…

We have modelled the evolution of cometary HII regions produced by zero-age main-sequence stars of O and B spectral types, which are driving strong winds and are born off-centre from spherically symmetric cores with power-law ($\alpha = 2$)…

Astrophysics of Galaxies · Physics 2017-03-17 Harrison Steggles , Melvin Hoare , Julian Pittard
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