Article
Astronomy & Astrophysics
F. D. Priestley, A. P. Whitworth
Summary: Research suggests that collisions between interstellar gas clouds can rapidly generate large masses of dense gas, triggering star formation. By analyzing molecular line observations and conducting simulations, it is possible to distinguish genuinely colliding clouds from chance superpositions, and confirm observational evidence of cloud collisions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
F. D. Priestley, D. Arzoumanian, A. P. Whitworth
Summary: Filamentary structures in molecular clouds, which are important for star formation, are expected to form where the supersonic turbulent velocity field converges. While the existing model reproduces some properties of these structures, it is unclear whether it can reproduce their kinematic features. In this study, we use modeling to predict the emission properties of dynamically forming filaments, and the results are largely consistent with observations, suggesting that equilibrium analysis and simulations assuming the existence of filaments may be unrealistic.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Y. X. Wang, J. S. Zhang, Y. T. Yan, J. J. Qiu, J. L. Chen, J. Y. Zhao, Y. P. Zou, X. C. Wu, X. L. He, Y. B. Gong, J. H. Cai
Summary: This study aims to investigate the evolution of HC3N in high-mass star-forming regions (HMSFRs) at different evolutionary stages and detect the existence of HC5N and HC7N in HMSFRs. The results show that the detection rate, column density, and relative abundance of HC3N are higher in Maser-RRL sources and lower in RRL-only sources.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
A. Clement, A. Taillard, V. Wakelam, P. Gratier, J. -c. Loison, E. Dartois, F. Dulieu, J. A. Noble, M. Chabot
Summary: This study models the formation process of interstellar ices, focusing on H2O, CO2, CO, and CH3OH. The research finds that dust temperature and visual extinction significantly influence the composition of ice, with the formation of CO2 being particularly affected by dust temperature under low visual extinction conditions.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
H. Luthra, V Wakelam, M. K. Sharma, S. Chandra
Summary: Since the 1930s, more than 250 molecules have been discovered in the interstellar medium, and with the development of more sensitive telescopes, we keep detecting new, more complex species. Among them, methanimine (CH2NH) is considered a pre-biotic molecule and has been observed in various interstellar sources. However, previous models failed in reproducing the observed abundance of CH2NH in cold cores. In this study, we tested new proposed reactions and explored the sensitivity of CH2NH abundance to different factors, and successfully reproduced the detections in cold cores Ori-3N and L183.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
N. Marcelino, B. Tercero, M. Agundez, J. Cernicharo
Summary: The study presents Yebes 40 m telescope observations of the three most stable C4H3N isomers towards the cyanopolyyne peak of TMC-1, confirming the detection of HCCCH2CN and CH2CCHCN in space. The abundance of the three isomers suggests a common origin involving reactions of the radical CN with unsaturated hydrocarbons. Chemical model provides abundances close to observations but with some discrepancies. Further studies and observations are needed to draw a clear picture of the chemistry of C4H3N isomers in space.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
T. Moeller, P. Schilke, A. Schmiedeke, E. A. Bergin, D. C. Lis, A. Sanchez-Monge, A. Schwoerer, C. Comito
Summary: A comprehensive analysis of the broadband spectral line survey of Sagittarius B2 (Main) using HIFI revealed the presence of a variety of chemical species, with sulfur dioxide, methanol, and water being the dominant contributors. Deviations in ortho/para ratios ranged from 37% to 180%, and 14% of all lines remained unidentified.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
O. Sipilae, L. Colzi, E. Roueff, P. Caselli, F. Fontani, E. Wirstroem
Summary: In this study, a new gas-grain chemical model for the combined isotopic fractionation of carbon and nitrogen in molecular clouds is presented. The results show significant deviations and time-dependent variations in isotopic abundance ratios as a function of physical conditions and time. Additionally, the abundance ratios between different isotopic forms of molecules also exhibit some levels of fractionation due to newly included exchange reactions.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
F. D. Priestley, P. C. Clark, S. C. O. Glover, S. E. Ragan, O. Feher, L. R. Prole, R. S. Klessen
Summary: Much of our knowledge about molecular clouds and star formation comes from molecular line observations, which require understanding of molecular abundances. To address this, we develop a framework for post-processing simulations with a time-dependent chemical network, allowing us to model the behavior of important species. Our findings reveal different evolutionary patterns for molecules, with some reaching peak abundances at moderate densities and declining sharply afterwards, while others peak at higher densities and remain roughly constant. Neglecting the dynamical evolution of molecular gas in chemistry modeling can lead to significant overestimation of gas-phase abundances and miss important abundance variations caused by different evolutionary histories.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
F. D. Priestley, P. C. Clark, S. C. O. Glover, S. E. Ragan, O. Feher, L. R. Prole, R. S. Klessen
Summary: The study finds that molecular species commonly assumed to trace the dense, star-forming component of molecular clouds actually exist in material transiently enhanced in density. Only N2H+ exists in detectable quantities above a certain volume density, and N2H+ emission can be used to predict star formation in molecular clouds.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Keshav Kumar Singh, Poonam Tandon, Rajesh Kumar, Alka Misra, Shivani, Manisha Yadav, Aftab Ahmad, Manoj Kumar Chaudhary
Summary: Aminomethanol is an important precursor of interstellar glycine, and a two-step formation pathway has been proposed for its formation in interstellar ice. The study found that the proposed pathway is efficient in ice, with CH2NH identified as the starting reactant for aminomethanol.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
F. D. Priestley, P. C. Clark, A. P. Whitworth
Summary: Simulations of molecular clouds often start from highly idealized initial conditions but recent observational work has discovered a tight relationship between molecular line intensity and column density. By combining simulations, chemistry, and radiative transfer, it is found that the idealized models commonly used in the literature are reasonably accurate representations of real molecular clouds.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yang Yang, Yao Wang, Zhibo Jiang, Zhiwei Chen
Summary: The study focuses on understanding the initial stages of star formation through investigating the physical and chemical properties of gas infall motion in molecular clumps. The FTS wide-sideband mode of the IRAM 30-m telescope was used to observe nine infall sources with significant double-peaked blue line profiles. Molecular line data was obtained, and multiple molecules and isotopic transition lines were identified in these sources. Chemical simulations were used to fit the observed molecular abundances, indicating that most sources are in the early HMPO stage with temperatures around several 10 K.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
S. Ebagezio, D. Seifried, S. Walch, P. C. Nuernberger, T-E Rathjen, T. Naab
Summary: In this study, synthetic (CO)-C-12, (CO)-C-13, and [C II] emission maps are analysed to study molecular cloud simulations. The findings indicate that feedback bubbles are mostly devoid of [C II] emission, which is attributed to further ionization of C + into C-2 +. Additionally, the assumption of chemical equilibrium leads to overestimation of H-2 and CO masses and underestimation of H and C (+) masses, as well as intrinsic errors in luminosities and luminosity ratios.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Gilberto C. Gomez, Catherine Walsh, Aina Palau
Summary: This study explores how the measurement of dense filament widths using different molecular species can be influenced by gas accretion. The abundance of various molecules is affected differently by the changing environment as a gas parcel falls into the filament. The widths of filaments measured from time-dependent abundances of certain molecules are most sensitive to this effect, while others are less sensitive. The ratios of filament widths for different tracers could be a useful tool for estimating the accretion rate onto the filament.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
D. Alberton, L. Bizzocchi, N. Jiang, M. Melosso, V. M. Rivilla, A. Pietropolli Charmet, B. M. Giuliano, P. Caselli, C. Puzzarini, S. Alessandrini, L. Dore, I. Jimenez-Serra, J. Martin-Pintado
Summary: This study aims to investigate the rotational spectrum of allylimine in the laboratory and to obtain accurate spectral data for the detection of this molecule in the interstellar medium. By recording the rotational spectra and conducting calculations, a precise set of spectroscopic parameters was determined for allylimine. Based on the improved spectral data, a tentative detection of allylimine was reported in a molecular cloud in the Galactic centre.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Mohit K. Sharma, Mattia Melosso, Suresh Chandra
Summary: Accurate computational characterization of ethanimine, an important possible precursor of amino acids, has been done. Radiative transition probabilities for rotational transitions were calculated and used in solving statistical equilibrium equations and radiative transfer equations. Weak MASER lines and anomalous absorption lines were found that may be important for identifying ethanimine in cosmic objects.
Article
Chemistry, Physical
Mattia Melosso, Ningjing Jiang, Juergen Gauss, Cristina Puzzarini
Summary: Despite their simplicity, the spectroscopic investigation of light hydrides like hydrogen sulfide is challenging due to hyperfine interactions and anomalous centrifugal-distortion effects. Accurate knowledge of the rotational spectrum, especially for isotopic species with deuterium, is important for understanding astronomical objects and interstellar chemistry. This study combines quantum-chemical calculations and sub-Doppler measurements to investigate the hyperfine structure of the rotational spectrum of mono-deuterated hydrogen sulfide, extending the centrifugal analysis and modeling the spectrum accurately across different wavelengths.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Biochemistry & Molecular Biology
Silvia Alessandrini, Mattia Melosso, Victor M. Rivilla, Luca Bizzocchi, Cristina Puzzarini
Summary: By applying a new computational protocol based on the minimum-energy principle, we identified vinylisocyanate as the most stable isomer in the C3H3NO family, followed by oxazole. Pyruvonitrile, cyanoacetaldehyde, and cyanovinylalcohol were also found to be stable according to our calculations. We provided new rotational and vibrational spectroscopic data for these species.
Article
Astronomy & Astrophysics
H. S. P. Mueller, R. T. Garrod, A. Belloche, V. M. Rivilla, K. M. Menten, I Jimenez-Serra, J. Martin-Pintado, F. Lewen, S. Schlemmer
Summary: Methylamine was the only alkylamine found in the interstellar medium until recently, with the addition of vinylamine and ethylamine, dimethylamine has become a target for space exploration. The rotational spectrum of dimethylamine has been studied up to 45 GHz until now, and this study expands the range to 76-1091 GHz. Non-detections of dimethylamine in certain regions suggest that it is less abundant than methylamine in those sources. Comparison with computational models indicates that the levels of dimethylamine in the models may be too high.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
S. Zeng, V. M. Rivilla, I Jimenez-Serra, L. Colzi, J. Martin-Pintado, B. Tercero, P. de Vicente, S. Martin, M. A. Requena-Torres
Summary: Interstellar amides, including acetamide and trans-N-methylformamide, have been detected in a quiescent Galactic centre molecular cloud, suggesting that amides related chemistry is triggered in early evolutionary stages of molecular clouds. The constant abundance ratios of amides observed independently of the evolutionary stages indicate that they remain unaffected by the warm-up phase during the star formation process. The detection of amides together with other precursors can help constrain the amide chemistry in the interstellar medium.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
D. San Andres, L. Colzi, V. M. Rivilla, J. Garcia de la Concepcion, M. Melosso, J. Martin-Pintado, I Jimenez-Serra, S. Zeng, S. Martin, M. A. Requena-Torres
Summary: The H2NC radical, a high-energy metastable isomer of the H2CN radical, has been detected for the first time in the interstellar medium, indicating a potential dependence of the H2CN/H2NC isomeric ratio on kinetic temperature. However, the lack of detections in warm sources has limited our understanding of their chemistry. In this study, H2CN and H2NC were detected towards a warm galactic source, confirming a higher H2CN/H2NC ratio in warm sources compared to colder cores. Grain surface reactions may play a role in explaining these observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Antonio Martinez-Henares, Izaskun Jimenez-Serra, Jesus Martin-Pintado, Nuria Huelamo, Sirina Prasad, Qizhou Zhang, James Moran, Yue Cao, Alejandro Baez-Rubio
Summary: Researchers have discovered a high-velocity ionized jet in the MWC 349A system using ALMA, which has implications for understanding the formation and evolution of massive stars.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
D. Alberton, V. Lattanzi, C. Endres, V. M. Rivilla, J. C. Guillemin, P. Caselli, I. Jimenez-Serra, J. Martin-Pintado
Summary: A laboratory investigation was conducted to obtain precise frequency data of Z-aminoacrylonitrile, an alkenyl cyanide, for interstellar detection. The data was then used to search for Z-aminoacrylonitrile in the G+0.693-0.027 molecular cloud located near the Galactic center.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Miguel Sanz-Novo, Victor M. Rivilla, Izaskun Jimenez-Serra, Jesus Martin-Pintado, Laura Colzi, Shaoshan Zeng, Andres Megias, Alvaro Lopez-Gallifa, Antonio Martinez-Henares, Sarah Massalkhi, Belen Tercero, Pablo de Vicente, Sergio Martin, David San Andres, Miguel A. Requena-Torres
Summary: After 25 years since the detection of the last interstellar carboxylic acid, acetic acid, a new one, the cis-trans form of carbonic acid, has been discovered in the Galactic center molecular cloud. This molecule is the first interstellar molecule containing three oxygen atoms and the third carboxylic acid detected in the interstellar medium. Although limited laboratory measurements have been conducted, several unblended lines in astronomical data have been directly identified, leading to a slight improvement in spectroscopic constants. The abundance of cis-trans HOCOOH with respect to molecular H-2 is estimated to be 4.7 x 10(-11), while the abundance of cis-cis HOCOOH is nearly undetectable, but potentially abundant in interstellar space.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Sirina Prasad, Qizhou Zhang, James Moran, Yue Cao, Izaskun Jimenez-Serra, Jesus Martin-Pintado, Antonio Martinez-Henares, Alejandro Baez-Rubio
Summary: MWC 349A is a star with rare hydrogen radio recombination line (RRL) masers. Using ALMA observations, we resolved the H30α and 1.4 mm continuum emission for the first time and found evidence of a high-velocity jet along the polar axis. These masers may originate from a magnetohydrodynamic wind.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Chemistry, Physical
Mattia Melosso, Silvia Alessandrini, Lorenzo Spada, Alessio Melli, Xiujuan Wang, Yang Zheng, Chunguo Duan, Jiayi Li, Weiping Du, Qian Gou, Luca Bizzocchi, Luca Dore, Vincenzo Barone, Cristina Puzzarini
Summary: This study used high-resolution rotational spectroscopic techniques and high-level quantum-chemical calculations to characterize the spectroscopy and structure of two isomers of cyanofuran. Furthermore, the rotational spectra of different intermolecular adducts formed by furonitrile and water were also investigated.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
