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Related papers: HII region variability and pre-main-sequence evolu…

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We investigate the possibility of constraining the ionization state of the intergalactic medium (IGM) close to the end of reionization (z ~ 6) by measuring the size of the HII regions in high-z quasars spectra. We perform a combination of…

Astrophysics · Physics 2008-11-26 A. Maselli , S. Gallerani , A. Ferrara , T. R. Choudhury

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…

The HII regions are all studied employing the same general prescriptions, despite the possible influence of their environment in their star formation processes. Through the analysis of two samples of 725 inner and 671 outer disk HII region…

Astrophysics of Galaxies · Physics 2019-10-16 M. Rodríguez-Baras , A. I. Díaz , F. F. Rosales-Ortega

It is possible that the properties of HII regions during reionization depend sensitively on many poorly constrained quantities (the nature of the ionizing sources, the clumpiness of the gas in the IGM, the degree to which photo-ionizing…

We present a multiwavelength study of the ultra compact HII region associated with IRAS 20178+4046. This enables us to probe the different components associated with this massive star forming region. The radio emission from the ionized gas…

Astrophysics · Physics 2009-11-13 A. Tej , S. K. Ghosh , V. K. Kulkarni , D. K. Ojha , R. P. Verma , S. Vig

The formation process of binary stars and multiple systems is poorly understood. Here, we seek to determine the typical outcome of protostellar collapse and to constrain models of binary formation by core fragmentation during collapse,…

Astrophysics of Galaxies · Physics 2015-05-18 A. J. Maury , Ph. Andre , P. Hennebelle , F. Motte , D. Stamatellos , M. Bate , A. Belloche , G. Duchene , A. Whitworth

The feedback from young stars (i.e. pre-supernova) is thought to play a crucial role in molecular cloud destruction. In this paper, we assess the feedback mechanisms acting within a sample of 5810 HII regions identified from the PHANGS-MUSE…

We present theoretical semi-analytic models for the interaction of stellar winds with the interstellar medium (ISM) or prior mass loss implemented in our code SPICE (Supernovae Progenitor Interaction Calculator for parameterized…

Solar and Stellar Astrophysics · Physics 2016-02-17 Paul Dragulin , Peter Hoeflich

Young massive stars or clusters are often observed at the peripheries of HII regions. What triggers star formation at such locations? Among the scenarios that have been proposed, the `collect and collapse' process is particularly attractive…

Astrophysics · Physics 2009-11-10 L. Deharveng , A. Zavagno , J. Caplan

Resolution of nearby giant HII regions into their stellar and nebular constituents provides fundamental insights for interpreting more distant and powerful starburst activity. The following summarizes recent advances in our understanding of…

Astrophysics · Physics 2007-05-23 William H. Waller

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

Stars and their corresponding protoplanetary disks form in diverse environments. To account for these natural variations, we investigate the formation process around nine solar mass stars with a maximum resolution of 2 AU in a Giant…

Astrophysics of Galaxies · Physics 2017-11-10 Michael Küffmeier , Troels Haugbølle , Åke Nordlund

The James Clerk Maxwell Telescope has been used to obtain submillimeter and millimeter continuum photometry of a sample of 30 IRAS sources previously studied in molecular lines and centimeter radio continuum. All the sources have IRAS…

Astrophysics · Physics 2007-05-23 Sergio Molinari , Jan Brand , Riccardo Cesaroni , Francesco Palla

Context. G24.78+0.08 A1 is a 20 Msun star surrounded by a hypercompact (HC) HII region, driving a CO bipolar outflow, and located at the center of a massive rotating toroid undergoing infall towards the HC region. Recent water maser…

Astrophysics · Physics 2009-11-13 M. T. Beltran , R. Cesaroni , L. Moscadelli , C. Codella

Here we address the question whether the ionized shells associated with giant HII regions can be progenitors of the larger HI shell-like objects found in the Milky Way and other spiral and dwarf irregular galaxies. We use for our analysis a…

Astrophysics · Physics 2009-11-13 Sergiy Silich , Federico Elias , José Franco

The James Webb Space Telescope (JWST) is discovering an increasing number of galaxies well into the early stages of the Epoch of Reionization (EoR). Many of these galaxies are clustered with strong Lyman alpha (Ly$\alpha$) emission,…

Mass accretion onto (proto-)stars at high accretion rates > 10^-4 M_sun/yr is expected in massive star formation. We study the evolution of massive protostars at such high rates by numerically solving the stellar structure equations. In…

Solar and Stellar Astrophysics · Physics 2015-05-19 Takashi Hosokawa , Harold W. Yorke , Kazuyuki Omukai

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…

The evolution of radiation emitted during the dynamical collapse of metal-free protostellar clouds is investigated within a spherically symmetric hydrodynamical scheme that includes the transfer of radiation and the chemistry of the…

Astrophysics · Physics 2009-11-06 Emanuele Ripamonti , Francesco Haardt , Andrea Ferrara , Monica Colpi

To understand evolutionary and environmental effects during the formation of high-mass stars, we observed three regions of massive star formation at different evolutionary stages that reside in the same natal molecular cloud. Methods. The…

Solar and Stellar Astrophysics · Physics 2012-05-25 Y. Wang , H. Beuther , A. Bik , T. Vasyunina , Z. Jiang , E. Puga , H. Linz , J. A. Rodon , Th. Henning , M. Tamura