Article
Astronomy & Astrophysics
F. Fontani, A. Schmiedeke, A. Sanchez-Monge, L. Colzi, D. Elia, V. M. Rivilla, M. T. Beltran, L. Bizzocchi, P. Caselli, L. Magrini, D. Romano
Summary: The study reveals that the chemical properties of the outer star-forming regions of the Galaxy are similar to those of the inner and local regions. Methanol (CH3OH) is detected in the observed targets, and its emission is associated with an extended envelope, indicating that it mainly comes from a cold and quiescent region. The relative abundance of CH3OH shows good correlations with that of H2CO, but not with HCO. These findings have significant implications for understanding the organic and possibly pre-biotic chemistry in the outermost star-forming regions of the Galaxy.
ASTRONOMY & ASTROPHYSICS
(2022)
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
M. Wienen, C. M. Brunt, C. L. Dobbs, D. Colombo
Summary: Expanding (sub)millimetre capabilities to high angular resolution with interferometers enables the resolution of giant molecular clouds in nearby galaxies. By remapping CO-C-12 data along the Perseus spiral arm in the Milky Way, at a common distance to an observer outside the galaxy, important insights into the structure of the arm, including thickness, centroid position, and mass distribution, were determined.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
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, 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
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
Shaila Akhter, Maria R. Cunningham, Lisa Harvey-Smith, Mohammad Ali Nawaz, Paul A. Jones, Andrew Walsh, Elisabete M. de Gouveia Dal Pino
Summary: In this study, NH(1,1) data from the HO Southern Galactic Plane Survey (HOPS) was used to identify dense molecular clumps in the Milky Way Galaxy that have the potential to form high-mass stars, resulting in the identification of approximately 500 clumps. Analysis focused on 14 of these clumps near the Central Molecular Zone, revealing broad emission spectral lines and grouping these clumps into three clusters of dense molecular cores. The velocity dispersion and emission line broadening of these clusters suggest a possible association with the Galactic bar potential x-1 orbits, with Cluster-3 showing signs of undergoing high-mass star formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
F. Fontani, L. Colzi, L. Bizzocchi, V. M. Rivilla, D. Elia, M. T. Beltran, P. Caselli, L. Magrini, A. Sanchez-Monge, L. Testi, D. Romano
Summary: This paper presents a new observational project called CHEMOUT, which aims to investigate the chemical composition in star-forming regions of the outer Galaxy. The results show that organic molecules and tracers of protostellar activity are ubiquitous in the low metallicity environment of the outer Galaxy.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
David J. Whitworth, Rowan J. Smith, Ralf S. Klessen, Mordecai-Mark Mac Low, Simon C. O. Glover, Robin Tress, Ruediger Pakmor, Juan D. Soler
Summary: Many studies have shown that magnetic fields can suppress star formation in molecular clouds and Milky Way like galaxies. However, most of these studies have focused on fully developed fields at saturation level, and there is little understanding of how weak initial primordial fields affect star formation in low metallicity environments. In this paper, the impact of a weak initial field on low metallicity dwarf galaxies is investigated. High-resolution AREPO simulations are performed, and the results show that the magnetic field has little impact on the global star formation rate (SFR), contrary to some previous studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Takeru Murase, Toshihiro Handa, Ren Matsusaka, Yoshito Shimajiri, Masato I. N. Kobayashi, Mikito Kohno, Junya Nishi, Norimi Takeba, Yosuke Shibata
Summary: In this study, the H-2 column density probability distribution function (N-PDF) was analyzed based on molecular emission lines using the Nobeyama 45-m Cygnus X CO survey data. A total of 124 molecular clouds were identified using the DENDROGRAM and SCIMES algorithms. For 11 molecular clouds with an extent of more than 0.4 deg(2), an N-PDF was constructed and fitted with one or two lognormal distributions. The findings suggest that the shape of the N-PDF reflects the density and turbulent structure of the whole molecular cloud, while being less affected by star-forming activities.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
F. Fontani, A. T. Barnes, P. Caselli, J. D. Henshaw, G. Cosentino, I Jimenez-Serra, J. C. Tan, J. E. Pineda, C. Y. Law
Summary: The study reveals large variations in the N-14/N-15 ratio in star-forming regions, with values ranging from approximately 80 to 400 in cores associated with IRDCs. The average N-14/N-15 ratio of around 210 is slightly lower than the interstellar value.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Y. Ge, K. Wang, A. Duarte-Cabral, A. R. Pettitt, C. L. Dobbs, A. Sanchez-Monge, K. R. Neralwar, J. S. Urquhart, D. Colombo, E. Duran-Camacho, H. Beuther, L. Bronfman, A. J. Rigby, D. Eden, S. Neupane, P. Barnes, T. Henning, A. Y. Yang
Summary: This study used a modified minimum spanning tree algorithm to connect filamentary structures in the interstellar medium and identified 88 large-scale filaments in the inner Galactic plane. It was found that eight of these filaments are associated with spiral arms and can be considered as the bones of the Milky Way. The study also revealed that bones have higher dense gas mass fraction than other filaments.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
R. Bogner, T. Csengeri, J. Montillaud, M. Wienen, N. Schneider, F. Wyrowski, F. Motte, L. V. Toth
Summary: This research focuses on characterizing the most massive cores in the Rosette molecular cloud complex to understand the star formation processes in the region. The results suggest that star formation is more likely based on the primordial structure of the cloud despite the impact of nearby stellar clusters, and that the gas properties in the molecular cloud fall between those of low- and high-mass star-forming regions.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
L. Evans, F. Fontani, C. Vastel, C. Ceccarelli, P. Caselli, A. Lopez-Sepulcre, R. Neri, F. Alves, L. Chahine, C. Favre, V Lattanzi
Summary: This study investigated the variation in the N-14/N-15 ratio in the OMC-2 FIR4 protocluster and found a small regional variation for HCN and N2H+. The results suggest that the physical parameters on small linear scales in the protocluster do not seem to affect the N-14/N-15 ratio in either HCN or N2H+.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
O. L. Ryabukhina, M. S. Kirsanova, C. Henkel, D. S. Wiebe
Summary: In this study, observations and astrochemical modeling were used to investigate the physical properties, collapse features, and chemical ages of dense clumps in an interstellar filament. The results suggest rapid interstellar matter accumulation and collapse over a time scale of approximately 10(5) years, which is important for understanding the evolution of interstellar matter.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Mengyao Tang, Aina Palau, Luis A. Zapata, Sheng-Li Qin
Summary: The study focuses on the fragmentation process in massive star-forming regions, specifically investigating W51 IRS2 using high angular resolution data from ALMA. A total of 33 continuum sources were identified, with 29 defined as fragments. Analysis of mean surface density of companions revealed two breaks indicating a two-level clustering phenomenon in the region.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Shanghuo Li, Patricio Sanhueza, Chang Won Lee, Qizhou Zhang, Henrik Beuther, Aina Palau, Hong-Li Liu, Howard A. Smith, Hauyu Baobab Liu, Izaskun Jimenez-Serra, Kee-Tae Kim, Siyi Feng, Tie Liu, Junzhi Wang, Di Li, Keping Qiu, Xing Lu, Josep Miquel Girart, Ke Wang, Fei Li, Juan Li, Yue Cao, Shinyoung Kim, Shaye Strom
Summary: This study presents the observation results of narrow filaments in the NGC 6334S infrared dark cloud using ALMA. The filaments are found to be narrower and have lower turbulence compared to previously proposed filaments. Embedded cores show smaller widths and lower velocity dispersions compared to their corresponding filaments. The physical properties of the filaments are analogous to those found in low- to high-mass star-forming regions.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Junhao Liu, Keping Qiu, Qizhou Zhang
Summary: The DCF method provides a way to estimate magnetic field strength indirectly. Compilation of previous estimations using this method and recalculation with new correction factors reveals a proportionality between magnetic field strength and volume density. However, the power-law index of the observed B-n relation has uncertainties and might not correspond to theoretical models. The study also finds a trend of decreasing magnetic viral parameter with increasing column density, indicating dominance of magnetic field at lower densities and dissipation at higher densities.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Jian-Wen Zhou, Tie Liu, Neal J. Evans, Guido Garay, Paul F. Goldsmith, Gilberto C. Gomez, Enrique Vazquez-Semadeni, Hong-Li Liu, Amelia M. Stutz, Ke Wang, Mika Juvela, Jinhua He, Di Li, Leonardo Bronfman, Xunchuan Liu, Feng-Wei Xu, Anandmayee Tej, L. K. Dewangan, Shanghuo Li, Siju Zhang, Chao Zhang, Zhiyuan Ren, Ken'ichi Tatematsu, Pak Shing Li, Chang Won Lee, Tapas Baug, Sheng-Li Qin, Yuefang Wu, Yaping Peng, Yong Zhang, Rong Liu, Qiu-Yi Luo, Jixing Ge, Anindya Saha, Eswaraiah Chakali, Qizhou Zhang, Kee-Tae Kim, Isabelle Ristorcelli, Zhi-Qiang Shen, Jin-Zeng Li
Summary: It is found that hub-filament systems are common in proto-clusters and decrease with increasing dust temperature and luminosity-to-mass ratios, indicating the influence of stellar feedback. The study also reveals different velocity gradients for filaments of different lengths, suggesting the presence of inertial inflows and dominance of gravity at small scales. Self-similar hub-filament systems and filamentary accretion may play a key role in high-mass star formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
M. L. van Gelder, J. Jaspers, P. Nazari, A. Ahmadi, E. F. van Dishoeck, M. T. Beltran, G. A. Fuller, A. Sanchez-Monge, P. Schilke
Summary: Through the study of methanol in a sample of 99 high-mass protostars, it is found that the D/H ratio is related to the physical conditions during the prestellar phase. The methanol D/H ratio is one order of magnitude lower in high-mass protostars compared to low-mass protostellar systems, while successive deuteration towards CHD2OH is equally effective in both high-mass and low-mass systems.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
F. Meng, A. Sanchez-Monge, P. Schilke, A. Ginsburg, C. DePree, N. Budaiev, D. Jeff, A. Schmiedeke, A. Schwoerer, V. S. Veena, Th Moeller
Summary: This study aims to characterize the properties of HII regions in the molecular cloud Sagittarius B2, with a focus on identifying and analyzing various UCHIT regions in the complex to reveal different evolutionary stages of the cloud.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
P. Nazari, J. D. Meijerhof, M. L. van Gelder, A. Ahmadi, E. F. van Dishoeck, B. Tabone, D. Langeroodi, N. F. W. Ligterink, J. Jaspers, M. T. Beltran, G. A. Fuller, A. Sanchez-Monge, P. Schilke
Summary: This study investigates the distribution of six N-bearing species in a large sample of high-mass protostars using the Atacama Large Millimeter/submillimeter Array (ALMA). The results show the widespread presence of these species in the sample and their grouping based on excitation temperature. The constant column density ratios suggest a common formation environment for these complex organics or their precursors in pre-stellar ices.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Roberto Galvan-Madrid, Qizhou Zhang, Andres Izquierdo, Charles J. Law, Thomas Peters, Eric Keto, Hauyu Baobab Liu, Paul T. P. Ho, Adam Ginsburg, Carlos Carrasco-Gonzalez
Summary: We conducted observations and radiative-transfer modeling to study the ionized accretion flow around a compact star cluster in formation. The modeling suggests the presence of an ionized Keplerian disk with or without radial motions, or an external Ulrich envelope. The fitting results give a range of total stellar masses and ionized-gas masses, indicating that the gas is marginally unbound. Our analysis also reveals the presence of a few massive stars accompanied by a population of lower-mass stars within the cluster, with a very high cluster density comparable to the Galactic center.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Manuel E. Aravena, Jason E. Austermann, Kaustuv Basu, Nicholas Battaglia, Benjamin Beringue, Frank Bertoldi, Frank C. Bigiel, J. Richard Bond, Patrick C. Breysse, Colton C. Broughton, Ricardo Bustos, Scott C. K. Chapman, Maude T. Charmetant, Steve K. E. Choi, Dongwoo T. F. Chung, Susan E. T. Clark, Nicholas F. Cothard, Abigail T. Crites, Ankur J. Dev, Kaela Douglas, Cody J. Duell, Rolando Duenner, Haruki Ebina, Jens M. Erler, Michel Fich, Laura M. Fissel, Simon A. Foreman, R. G. Freundt, Patricio A. Gallardo, Jiansong Gao, Pablo E. Garcia, Riccardo E. Giovanelli, Joseph E. P. Golec, Christopher E. Groppi, Martha P. Haynes, Douglas Henke, Brandon Hensley, Terry Herter, Ronan Higgins, Renee Hlozek, Anthony Huber, Zachary Huber, Johannes Hubmayr, Rebecca Jackson, Douglas C. Johnstone, Christos Karoumpis, Laura C. Keating, Eiichiro Komatsu, Yaqiong C. Li, Benjamin D. Magnelli, Brenda C. J. Matthews, Philip D. Mauskopf, Jeffrey J. McMahon, P. Daniel Meerburg, Joel W. Meyers, Vyoma D. Muralidhara, Norman W. Murray, Michael D. Niemack, Thomas Nikola, Yoko A. Okada, Roberto Puddu, Dominik A. Riechers, Erik Rosolowsky, Kayla Rossi, Kaja I. Rotermund, Anirban Roy, Sarah Sadavoy, Reinhold Schaaf, Peter Schilke, Douglas K. Scott, Robert R. Simon, Adrian K. J. Sinclair, Gregory R. M. Sivakoff, Gordon J. Stacey, Amelia M. Stutz, Juergen Stutzki, Mehrnoosh A. Tahani, Karun N. Thanjavur, Ralf A. Timmermann, Joel N. M. Ullom, Alexander R. van Engelen, Eve M. D. Vavagiakis, Michael R. Vissers, Jordan D. Wheeler, Simon D. M. White, Yijie Zhu, Bugao Zou
Summary: We provide an overview of the Prime-Cam direct-detection camera-spectrometer, which will be used on the Fred Young Submillimeter Telescope. It will enable detailed studies of various astrophysical questions.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
Junhao Liu, Qizhou Zhang, Patrick M. Koch, Hauyu Baobab Liu, Zhi-Yun Li, Shanghuo Li, Josep Miquel Girart, Huei-Ru Vivien Chen, Tao-Chung Ching, Paul T. P. Ho, Shih-Ping Lai, Keping Qiu, Ramprasad Rao, Ya-wen Tang
Summary: In this study, we use ALMA observations to analyze the relative orientations between magnetic fields, column density gradients, local gravity, and velocity gradients in NGC 6334. Our results show that the alignment between the magnetic field and column density changes with the density of the region, indicating the influence of star formation activities. Additionally, we find that the magnetic field plays a significant role in the star formation process at small scales as well.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Kotomi Taniguchi, Patricio Sanhueza, Fernando A. Olguin, Prasanta Gorai, Ankan Das, Fumitaka Nakamura, Masao Saito, Qizhou Zhang, Xing Lu, Shanghuo Li, Huei-Ru Vivien Chen
Summary: We analyzed NH2CHO, HNCO, H2CO, and CH3CN ((CH3CN)-C-13) molecular lines in 30 high-mass star-forming regions using ALMA Band 6 data. NH2CHO was detected in 23 regions, while the other species were detected in 29 regions. A total of 44 hot molecular cores (HMCs) were identified using the CH3CN line maps. The fractional abundances of the four species were derived and strong correlations between NH2CHO and HNCO (rho = 0.89) and between NH2CHO and H2CO (0.84) were found, indicating direct chemical links.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Junhao Liu, Qizhou Zhang, Hauyu Baobab Liu, Keping Qiu, Shanghuo Li, Zhi-Yun Li, Paul T. P. Ho, Josep Miquel Girart, Tao-Chung Ching, Huei-Ru Vivien Chen, Shih-Ping Lai, Ramprasad Rao, Ya-wen Tang
Summary: We used molecular line data from different telescopes to study the velocity statistics in the massive star formation region NGC 6334 at various scales. The nonthermal motions revealed by the velocity dispersion function (VDF) remained supersonic across different scales. The nonthermal motions revealed by different instruments did not follow the same continuous power law, indicating the influence of massive star formation activities. The scaling relation of velocity fields in NGC 6334 deviated from a continuous and universal turbulence cascade due to the presence of massive star formation.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Lingzhen Zeng, Qizhou Zhang, Felipe O. Alves, Tao-Chung Ching, Josep M. Girart, Junhao Liu
Summary: This paper presents the results of full polarization observations of the massive star-forming region W75N. The magnetic field structures in the dense cores of the region are derived using the linearly polarized continuum emission. The overall magnetic field strength and orientation agree with previous observations, and the cloud is undergoing global gravitational collapse.
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
Astronomy & Astrophysics
Geovanni Cortes-Rangel, Luis A. Zapata, Pedro R. Rivera-Ortiz, Megan Reiter, Satoko Takahashi, Josep M. Masque
Summary: We present a more extensive study of dusty and gaseous pillars and globules in the Carina Nebula using ALMA observations. These observations reveal the molecular outflows, dusty envelopes+disks, and extended HH objects in these regions. The results suggest that the exciting sources may be low- or intermediate-mass protostars.
ASTROPHYSICAL JOURNAL
(2023)