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We have studied four complex organic molecules (COMs), methyl formate ($CH_3OCHO$), dimethyl ether ($CH_3OCH_3$), formamide ($NH_2CHO$), and ethyl cyanide ($C_2H_5CN$), towards a large sample of 39 high-mass star-forming regions…

Astrophysics of Galaxies · Physics 2020-09-09 A. Coletta , F. Fontani , V. M. Rivilla , C. Mininni , L. Colzi , Á. Sánchez-Monge , M. T. Beltrán

We have coupled a chemical model with two dynamical models of collapsing low mass star-forming cores to predict abundances across the core of the commonly used infall tracers, CS and HCO$^+$, at various stages of the collapse. The models…

Solar and Stellar Astrophysics · Physics 2015-05-19 Julia F. Roberts , Hugh A. W. Stace , Jonathan M. C. Rawlings

In star-forming regions, molecular cloud history and dynamics set the trend in the chemical composition. Ice formation, in particular, is affected by the evolution of physical conditions, which can lead to different ice compositions within…

Astrophysics of Galaxies · Physics 2025-07-02 A. Taillard , V. Wakelam , P. Gratier , E. Dartois , M. Chabot , J. A. Noble , L. Chu

We investigate general aspects of molecular line formation under conditions which are typical of prestellar cores. Focusing on simple linear molecules, we study formation of their rotational lines by radiative transfer simulations. We…

Astrophysics · Physics 2009-11-13 Ya. Pavlyuchenkov , D. Wiebe , B. Shustov , Th. Henning , R. Launhardt , D. Semenov

Methanol, one of the simplest complex organic molecules in the Interstellar Medium (ISM), has been shown to be present and extended in cold environments such as starless cores. We aim at studying methanol emission across several starless…

Astrophysics of Galaxies · Physics 2021-12-22 S. Spezzano , A. Fuente , P. Caselli , A. Vasyunin , D. Navarro-Almaida , M. Rodríguez-Baras , A. Punanova , C. Vastel , V. Wakelam

We report ALMA Band 6 continuum observations of 2000 AU resolution toward four massive molecular clouds in the Central Molecular Zone of the Galaxy. To study gas fragmentation, we use the dendrogram method to identify cores as traced by the…

(Abridged) The Central Molecular Zone (CMZ) of the Milky Way exhibits extreme conditions, including high gas densities, elevated temperatures, enhanced cosmic-ray ionization rates, and large-scale dynamics. Large-scale molecular surveys…

The physical and chemical properties of cold and dense molecular clouds are key to understanding how stars form. Using the IRAM 30 m and NRO 45 m telescopes, we carried out a Multiwavelength line-Imaging survey of the 70 $\mu$m dark and…

We found that in regions of high mass star formation the CS emission correlates well with the dust continuum emission and is therefore a good tracer of the total mass while the N$_2$H$^+$ distribution is frequently very different. This is…

The level of mass segregation in the core of globular clusters has been previously proposed as a potential indicator of the dynamical constituents of the system, such as presence of a significant population of stellar-mass black holes…

Astrophysics of Galaxies · Physics 2019-03-27 Ruggero de Vita , Michele Trenti , Morgan MacLeod

The inheritance of material across the star and planet formation process is traced by deuterium fractionation. We report here the first detection of doubly deuterated methanol towards pre-stellar cores. We study the deuterium fractionation…

Astrophysics of Galaxies · Physics 2023-01-11 Yuxin Lin , Silvia Spezzano , Paola Caselli

We investigate differences in the molecular abundances between magnetically super- and sub-critical prestellar cores, performing three-dimensional non-ideal magnetohydrodynamical (MHD) simulations with varying densities and magnetic field…

Astrophysics of Galaxies · Physics 2019-07-17 Felix D. Priestley , James Wurster , Serena Viti

Cold cores are an early step of star formation, characterized by densities > 10$^4$ cm$^{-3}$, low temperatures (< 15 K), and very low external UV radiation. We investigate the physico-chemical processes at play to tracing the origin of…

Astrophysics of Galaxies · Physics 2023-01-04 A. Taillard , V. WakelaM , P. Gratier , E. Dartois , M. Chabot , J. A. Noble , J. V. Keane , A. C. A. Boogert , D. Harsono

The study of physical and chemical properties of massive protostars is critical to better understand the evolutionary sequence which leads to the formation of high-mass stars. IRAS 18151-1208 is a nearby massive region (d = 3kpc, L ~ 20000…

Astrophysics · Physics 2009-11-13 M. Marseille , S. Bontemps , F. Herpin , F. F. S. van der Tak , C. R. Purcell

We have carried out observations of CCH and its two $^{13}$C isotopologues, $^{13}$CCH and C$^{13}$CH, in the 84 - 88 GHz band toward two starless cores, L1521B and L134N (L183), using the Nobeyama 45 m radio telescope. We have detected…

Astrophysics of Galaxies · Physics 2019-11-06 Kotomi Taniguchi , Eric Herbst , Hiroyuki Ozeki , Masao Saito

We pursue the investigation of a previously proposed correlation between chemical properties and physical evolutionary stage of isolated low-mass star-forming regions. In the past, the NH3/CCS abundance ratio was suggested to be a…

Astrophysics of Galaxies · Physics 2015-05-30 C. Marka , K. Schreyer , R. Launhardt , D. A. Semenov , Th. Henning

Thioxoethenylidene (CCS) is an abundant interstellar molecule, and a good tracer of high density and evolutionary stage of dense molecular clouds. It is also a suitable candidate for Zeeman splitting observations for its high splitting…

Astrophysics of Galaxies · Physics 2012-02-24 Nirupam Roy , Abhirup Datta , Emmanuel Momjian , Anuj P. Sarma

Isotopic fractionation is a very powerful tool to follow the evolution of material from one stage to the next in the star-formation process. Pre-stellar cores exhibit some of the highest levels of deuteration because their physical…

Astrophysics of Galaxies · Physics 2026-02-20 S. Spezzano , W. Riedel , P. Caselli , O. Sipilä , Y. Lin , H. A. Bunn , E. Redaelli , L. H. Coudert , A. Megías , I. Jimenez-Serra

We apply a number of atomic decomposition schemes across the standard QM7 dataset -- a small model set of organic molecules at equilibrium geometry -- to inspect the possible emergence of trends among contributions to atomization energies…

Chemical Physics · Physics 2023-04-19 Frederik Ø. Kjeldal , Janus J. Eriksen

We present high-resolution observations of interstellar CN, CH, CH^{+}, \ion{Ca}{1}, and \ion{Ca}{2} absorption lines toward the multiple star systems HD206267 and HD217035. Substantial variations in CN absorption are observed among three…

Astrophysics · Physics 2009-11-07 K. Pan , S. R. Federman , D. E. Welty