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Related papers: Ethynyl (C2H) in massive star formation: Tracing t…

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We review the phenomenon of ultra-compact H II regions (UCHIIs) as a key phase in the early lives of massive stars. This most visible manifestation of massive star formation begins when the Lyman continuum output from the massive young…

Astrophysics · Physics 2007-05-23 M. G. Hoare , S. E. Kurtz , S. Lizano , E. Keto , P. Hofner

CH2 transitions between 68 and 71 GHz were first detected toward the Orion-KL and W51 Main SFRs. Given their upper level energies of 225 K, they were thought to arise in dense, hot molecular cores near newly formed stars. However, this has…

Astrophysics of Galaxies · Physics 2021-03-10 A. M. Jacob , K. M. Menten , Y. Gong , P. Bergman , M. Tiwari , S. Bruenken , A. O. H. Olofsson

We have mapped 27 massive star-forming regions associated with water masers using three dense gas tracers: HC3N 10-9, HNC 1-0 and C2H 1-0. The FWHM sizes of HNC clumps and C2H clumps are about 1.5 and 1.6 times higher than those of HC3N,…

Solar and Stellar Astrophysics · Physics 2015-03-19 Juan Li , Junzhi Wang , Qiusheng Gu , Zhi-yu Zhang , Xingwu Zheng

Estimating molecular abundances ratios from the direct measurement of the emission of the molecules towards a variety of interstellar environments is indeed very useful to advance in our understanding of the chemical evolution of the…

Astrophysics of Galaxies · Physics 2018-09-12 S. Paron , M. B. Areal , M. E. Ortega

Red Midcourse Space Experiment (MSX) Sources (RMSs) are regarded as excellent candidates of massive starforming regions. In order to characterize the chemical properties of massive star formation, we made a systematic study of 87 RMSs in…

Astrophysics of Galaxies · Physics 2017-01-10 Naiping Yu , Jinlong Xu

C$_2$H is one of the first radicals to be detected in the interstellar medium. Its higher rotational transitions have recently become available with the Herschel Space Observatory. We aim to constrain the physical parameters of the C$_2$H…

Astrophysics of Galaxies · Physics 2015-06-17 Z. Nagy , V. Ossenkopf , F. F. S. Van der Tak , A. Faure , Z. Makai , E. A. Bergin

The role of feedback from massive stars is believed to be a key element in the evolution of molecular clouds. We use high-resolution 3D SPH simulations to explore the dynamical effects of a single O7 star located at the centre of a…

Astrophysics of Galaxies · Physics 2015-06-05 S. Walch , A. P. Whitworth , T. Bisbas , R. Wunsch , D. Hubber

The study of cyclic hydrocarbons is of utmost relevance in current astrochemical research, as they are considered to be among the most significant reservoirs of carbon in the interstellar medium. However, while unsaturated cyclic…

Astrophysics of Galaxies · Physics 2025-05-07 Mario Largo , Miguel Sanz-Novo , Pilar Redondo

We study the formation and evolution of HII regions around the first stars formed at z=10-30. We use a one-dimensional Lagrangian hydrodynamics code which self-consistently incorporates radiative transfer and non-equilibrium primordial gas…

Astrophysics · Physics 2009-11-10 T. Kitayama , N. Yoshida , H. Susa , M. Umemura

The recent detection of the hydrocarbon anion C6H- in the interstellar medium has led us to investigate the synthesis of hydrocarbon anions in a variety of interstellar and circumstellar environments. We find that the anion/neutral…

Astrophysics · Physics 2009-11-13 T. J. Millar , C. Walsh , M. A. Cordiner , R. Ní Chuimín , Eric Herbst

We present the results of N2H+(1-0) observations of 35 dense molecular cloud cores from the northern and southern hemispheres where massive stars and star clusters are formed. Line emission has been detected in 33 sources, for 28 sources…

Astrophysics · Physics 2009-11-07 L. Pirogov , I. Zinchenko , P. Caselli , L. E. B. Johansson , P. C. Myers

We have discovered 12 new molecular hydrogen emission-line objects (MHOs) in the vicinity of the candidate massive young stellar object Mol 121, in addition to five that were previously known. H2 2.12-micron/H2 2.25-micron flux ratios…

Astrophysics of Galaxies · Physics 2015-06-12 G. Wolf-Chase , K. Arvidsson , M. Smutko , R. Sherman

Massive galaxies in the early Universe have been shown to be forming stars at surprisingly high rates. Prominent examples are dust-obscured galaxies which are luminous when observed at sub-millimeter (sub-mm) wavelengths and which may be…

In order to investigate the physical and chemical properties of massive star forming cores in early stages, we analyse the excitation and abundance of four organic species, CH3OH, CH3OCH3, HCOOCH3 and CH3CH2CN, toward 29 Extended Green…

Solar and Stellar Astrophysics · Physics 2015-06-22 Jixing Ge , Jinhua He , Xi Chen , S. Takahashi

We present a multiwavelength study of five methanol maser sites which are not directly associated with a strong ($>100$ mJy) radio continuum source: G 31.28+0.06, G 59.78+0.06, G 173.49+2.42 (S231, S233IR), G 188.95+0.89 (S252, AFGL5180)…

Astrophysics · Physics 2009-11-10 V. Minier , M. G. Burton , T. Hill , M. R. Pestalozzi , C. R. Purcell , G. Garay , A. Walsh , S. Longmore

Infrared shells and bubbles are ubiquitous in the Galaxy and can generally be associated with HII regions formed around young, massive stars. In this paper, we use high-resolution 3D SPH simulations to explore the effect of a single O7 star…

Astrophysics of Galaxies · Physics 2015-06-16 S. Walch , A. P. Whitworth , T. G. Bisbas , R. Wunsch , D. A. Hubber

Quantifying the composition of the material in protoplanetary disks is paramount to determining the potential for exoplanetary systems to produce and support habitable environments. A key complex organic molecule (COM) to detect is methanol…

We present a new high-resolution study of pre-protocluster regions in tracers exclusively probing the coldest and dense gas (NH_2D). The data are used to constrain the chemical, thermal, kinematic, and physical conditions (i.e., densities)…

Astrophysics of Galaxies · Physics 2015-05-28 T. Pillai , J. Kauffmann , F. Wyrowski , J. Hatchell , A. G. Gibb , M. A. Thompson

We study the radial dependence in stellar populations of 33 nearby early-type galaxies with central stellar velocity dispersions sigma* > 150 km/s. We measure stellar population properties in composite spectra, and use ratios of these…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Jenny E Greene , Jeremy D Murphy , Genevieve J Graves , James E Gunn , Sudhir Raskutti , Julia M Comerford , Karl Gebhardt

Maser lines from different molecular species, including water, hydroxyl, and methanol, are common observational phenomena associated with massive star forming regions. In particular, the methanol maser appears as an ideal tool to study the…

Astrophysics of Galaxies · Physics 2014-06-04 L. Olmi , E. D. Araya , P. Hofner , S. Molinari , J. Morales Ortiz , L. Moscadelli , M. Pestalozzi