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We are studying the impact of HII regions on star formation in their associated molecular clouds. In this paper we present JCMT RxA molecular line observations of S175 and environs. This is the first within a sample of ten HII regions and…

Solar and Stellar Astrophysics · Physics 2015-05-13 Mohaddesseh Azimlu , Michel Fich , Carolyn McCoey

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…

Fragmentation and evolution for the molecular shells of the compact HII regions are less explored compared to their evolved counterparts. We map nine compact HII regions with a typical diameter of 0.4 pc that are surrounded by molecular…

A sample of 69 galaxies with radial velocities less than 2500 km/s was selected from the HI Parkes All Sky Survey (HIPASS) to deduce details about star formation in nearby disk galaxies selected with no bias to optical surface brightness…

Astrophysics · Physics 2009-11-11 J. F. Helmboldt , R. A. M. Walterbos , G. D. Bothun , K. O'Neil

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…

Star-forming regions are usually studied in the context of Galactic surveys, but dedicated observations are sometimes needed when the study reaches beyond the survey area. Here, we studied the G345.5+1.5 region, which is located slightly…

Astrophysics of Galaxies · Physics 2019-03-27 M. Figueira , C. López-Calderón , L. Bronfman , A. Zavagno , C. Hervías-Caimapo , N. Duronea , L-Å. Nyman

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…

The connection between high-mass stars and young stellar clusters has been well established by near-IR observations showing young massive stars in HII regions surrounded by clusters of lower mass stars. Mm-wave observations show that these…

Astrophysics · Physics 2007-05-23 A. R. Tieftrunk , S. T. Megeath , S. Thorwirth

Massive stars are formed in molecular clouds, and produce H II regions when they evolve onto the main sequence. The expansion of H II region can both suppress and promote star formation in the vicinity. M17 H II region is a giant cometary H…

Astrophysics of Galaxies · Physics 2023-06-22 Feng-Yao Zhu , Junzhi Wang , Yaoting Yan , Qing-Feng Zhu , Juan Li

In order to understand the star formation process under the influence of HII regions, we have carried out extensive investigations to well selected star-forming regions which all have been profoundly affected by existing massive O type…

Solar and Stellar Astrophysics · Physics 2015-10-14 Jin-Zeng Li , Jinghua Yuan , Hong-Li Liu , Yuefang Wu , Ya-Fang Huang

We present here our shape analysis method for a sample of 76 Galactic HII regions from MAGPIS 1.4 GHz data. The main goal is to determine whether physical properties and initial conditions of massive star cluster formation is linked to the…

Astrophysics of Galaxies · Physics 2018-05-02 Justyn Campbell-White , Dirk Froebrich , Alfred Kume

Young massive clusters (YMCs) are dense aggregates of young stars and are often speculated as potential precursors to globular clusters. However, the formation mechanism of massive and compact gas clumps that precede YMCs remains unknown.…

Astrophysics of Galaxies · Physics 2024-06-19 Ryunosuke Maeda , Tsuyoshi Inoue , Kazuyuki Omukai , Yasuo Fukui , Kisetsu Tsuge

The cosmic abundance of hydrides depends critically on high-energy UV, X-ray, and particle irradiation. Here we study hydrides in star-forming regions where irradiation by the young stellar object can be substantial, and density and…

Solar and Stellar Astrophysics · Physics 2015-06-17 Arnold O. Benz , Simon Bruderer , Ewine F. van Dishoeck , Pascal Staeuber , Susanne F. Wampfler

In this work, we aim to characterise high-mass clumps with infall motions. We selected 327 clumps from the Millimetre Astronomy Legacy Team 90-GHz (MALT90) survey, and identified 100 infall candidates. Combined with the results of He et al.…

Astrophysics of Galaxies · Physics 2016-06-15 Yu-Xin He , Jian-Jun Zhou , Jarken Esimbek , Wei-Guang Ji , Gang Wu , Xin-Di Tang , Toktarkhan Komesh , Ye Yuan , Da-Lei Li , W. A. Baan

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…

Observed variations in the HII region luminosity function (HII LF) seen in spiral arm vs. interarm regions, and different galactic Hubble type, can be explained simply by evolutionary effects and maximum number of ionizing stars per…

Astrophysics · Physics 2008-11-26 M. S. Oey , C. J. Clarke

To investigate the environment of HII region Sh2-163 and search for evidence of triggered star formation in this region, we performed a multi-wavelength study of this HII region. Most of our data were taken from large-scale surveys: 2MASS,…

Astrophysics of Galaxies · Physics 2017-02-14 Naiping Yu , Jun-Jie Wang , Nan Li

We present an analysis of the QUARKS survey sample, focusing on protoclusters where Hot Molecular Cores (HMCs, traced by CH3CN(12--11)) and UC HII regions (traced by H30\alpha/H40\alpha) coexist. Using the high-resolution, high-sensitivity…

The variations of the metallicity and ionization parameter in HII regions are usually thought to be the dominant factors that produce the variations we see in the observed emission line spectra. There is an increasing amount of evidence…

Astrophysics of Galaxies · Physics 2022-03-16 Xihan Ji , Renbin Yan

We present a study of active stellar forming regions in the environs of the HII region Sh2-205. The analysis is based on data obtained from point source catalogues and images extracted from 2MASS, MSX, and IRAS surveys. Complementary data…

Astrophysics of Galaxies · Physics 2009-11-13 G. A. Romero , C. E. Cappa