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Gravitational accretion accumulates the original mass, and this process is crucial for us to understand the initial phases of star formation. Using the specific infall profiles in optically thick and thin lines, we searched the clumps with…

Astrophysics of Galaxies · Physics 2020-09-02 Yang Yang , Zhibo Jiang , Zhiwei Chen , Shaobo Zhang , Shuling Yu , Yiping Ao

We present here a three-dimesional hydrodynamical simulation for star formation. Our aim is to explore the effect of the metal-line cooling on the thermodynamics of the star-formation process. We explore the effect of changing the…

Astrophysics of Galaxies · Physics 2018-11-26 P. Fibla , S. Bovino , R. Riaz , V. B. Díaz , C. Olave , S. Vanaverbeke , D. R. G. Schleicher

H$_{\rm I}$ 21-cm and $^{12}$CO 2.6-mm line emissions respectively trace the atomic and molecular gas phases, but they miss most of the opaque H$_{\rm I}$ and diffuse H$_2$ present in the Dark Neutral Medium (DNM) at the transition between…

High Energy Astrophysical Phenomena · Physics 2018-03-28 Q. Remy , I. A. Grenier , D. J. Marshall , J. M. Casandjian

Ices imprint strong absorption features in the near- and mid-infrared, but until recently they have been studied almost exclusively with spectroscopy toward small samples of bright sources. We show that JWST photometry alone can reveal and…

The destiny of complex organic molecules (COMs) in star-forming regions is interlinked with various evolutionary phases. Therefore, identifying these species in diversified environments of identical star-forming regions would help to…

Investigating star formation requires precise knowledge of the properties of the dense molecular gas. The low metallicity and wide range of star formation activity of the Large and Small Magellanic Clouds make them prime laboratories to…

As nearby neighbors to the Milky Way, the Large and Small Magellanic Clouds (LMC and SMC) provide a unique opportunity to study star formation in the context of their galactic ecosystems. Thousands of young stellar objects (YSOs) have been…

Astrophysics of Galaxies · Physics 2019-01-16 Megan Reiter , Omnarayani Nayak , Margaret Meixner , Olivia Jones

With a goal toward deriving the physical conditions in external galaxies, we present a survey of formaldehyde (H2CO) and ammonia (NH3) emission and absorption in a sample of starburst galaxies using the Green Bank Telescope. By extending…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Jeffrey G. Mangum , Jeremy Darling , Karl M. Menten , Christian Henkel , Meredith MacGregor

Isocyanic acid (HNCO) is a simple molecule with a potential to form prebiotic and complex organic species. Using a spectral survey collected with the Atacama Pathfinder EXperiment (APEX), in this work we report the detection of 42…

We present maps and spectra of the HCN(1-0) and HCO$^+$(1-0) lines in the extreme outer Galaxy, at galactocentric radii between 14 and 22 kpc, with the 13.7 meter Delingha telescope. The 9 molecular clouds were selected from a CO/$^{13}$CO…

Astrophysics of Galaxies · Physics 2023-08-09 Jonathan Braine , Yan Sun , Yoshito Shimajiri , Floris F. S. van der Tak , Min Fang , Philippe André , Hao Chen , Yu Gao

Molecular complexity builds up at each step of the Sun-like star formation process, starting from simple molecules and ending up in large polyatomic species. Complex organic molecules (COMs; such as methyl formate, HCOOCH$_3$, dymethyl…

Spectral line survey observations of 7 molecular clouds in the Large Magellanic Cloud (LMC) have been conducted in the 3 mm band with the Mopra 22 m telescope to reveal chemical compositions in low metallicity conditions. Spectral lines of…

Cornerstone molecules (CO, H_2CO, CH_3OH, HCN, HNC, CN, CS, SO) were observed toward seven sub-millimeter bright sources in the Orion molecular cloud in order to quantify the range of conditions for which individual molecular line tracers…

Astrophysics · Physics 2009-11-10 Doug Johnstone , Annemieke M. S. Boonman , Ewine F. van Dishoeck

Model carbon star atmospheres and synthetic spectra have been calculated using the recent HCN/HNC vibration rotation linelist of Harris et al. (2002) ApJ, 578, 657. The calculations are repeated using only HCN lines and show that HNC has a…

Astrophysics · Physics 2009-11-07 G. J. Harris , Ya. V. Pavlenko , H. R. A. Jones , J. Tennyson

We aim to investigate the chemistry of internal photon-dominated regions surrounding deeply embedded hypercompact and ultracompact HII regions. We search for specific tracers of this evolutionary stage of massive star formation that can be…

The physical structure of hot molecular cores, where forming massive stars have heated up dense dust and gas, but have not yet ionized the molecules, poses a prominent challenge in the research of high-mass star formation and…

Astrophysics of Galaxies · Physics 2018-07-04 Rainer Rolffs , Peter Schilke , Qizhou Zhang , Luis Zapata

Context. It is almost banal to say that the interstellar medium (ISM) is structurally and thermodynamically complex. But the variety of the governing processes, including stellar feedback, renders the investigation challenging. High…

Astrophysics of Galaxies · Physics 2023-08-30 Marco Monaci , Loris Magnani , Steven N. Shore , Henrik Olofsson , Mackenzie R. Joy

Accurate techniques which allow for the derivation of the spatial density in star formation regions are rare. A technique which has found application for the derivation of spatial densities in Galactic star formation regions utilizes the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Jeffrey G. Mangum , Jeremy Darling , Christian Henkel , Karl M. Menten

The increasing number of observations towards different environments in the Milky Way, as well as theoretical and experimental works, are improving our knowledge of the astrochemical processes in the interstellar medium (ISM). In this…

Astrophysics of Galaxies · Physics 2024-09-05 L. Colzi , V. M. Rivilla , M. T. Beltrán , C. Y. Law , E. Redaelli , M. Padovani

Context: We investigated the molecular gas associated with 6.7 GHz methanol masers throughout the Galaxy using a J=1-0 transition of the CO isotopologues. Methods:Using the 13.7-meter telescope at the Purple Mountain Observatory (PMO), we…

Solar and Stellar Astrophysics · Physics 2014-09-05 Zhiyuan Ren , Yuefang Wu , Tie Liu , Lixin Li , Di Li , Binggang Ju