Article
Astronomy & Astrophysics
Hong-Li Liu, Anandmayee Tej, Tie Liu, Patricio Sanhueza, Sheng-Li Qin, Jinhua He, Paul F. Goldsmith, Guido Garay, Sirong Pan, Kaho Morii, Shanghuo Li, Amelia Stutz, Ken'ichi Tatematsu, Feng-Wei Xu, Leonardo Bronfman, Anindya Saha, Namitha Issac, Tapas Baug, L. Viktor Toth, Lokesh Dewangan, Ke Wang, Jianwen Zhou, Chang Won Lee, Dongting Yang, Anxu Luo, Xianjin Shen, Yong Zhang, Yue-Fang Wu, Zhiyuan Ren, Xun-Chuan Liu, Archana Soam, Siju Zhang, Qiu-Yi Luo
Summary: We present a statistical study of 17 hub-filament-system (HFS) clouds of high-mass star formation using high-angular resolution ALMA data. The study reveals an evolutionary trend of increasing mass and mass surface density from the IR-dark to IR-bright stage. Mass-segregated clusters of YSOs are observed in both IR-dark and IR-bright HFSs, with massive YSOs located in the hub and low-mass YSOs distributed over larger areas. Outflow feedback preferentially escapes through inter-filamentary diffuse cavities, suggesting a limited effect on HFS disruption and high-mass star formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
Rin Yamada, Yasuo Fukui, Hidetoshi Sano, Kengo Tachihara, John H. Bieging, Rei Enokiya, Atsushi Nishimura, Shinij Fujita, Mikito Kohno, Kisetsu Tsuge
Summary: In this study, a kinematical analysis of the molecular gas in the Sh2-233 region was conducted, revealing the presence of a filamentary cloud and two dense cloud cores. The collision between these two clouds resulted in the compression of the gas, forming the filament and the dense cores. One of the dense cores is associated with a high-mass protostellar candidate. The findings suggest that cloud-cloud collision plays a crucial role in the formation of compact high-mass dense cores.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Swagat R. Das, Jessy Jose, Manash R. Samal, Shaobo Zhang, Neelam Panwar
Summary: This study tested various star formation scaling relations and found correlations between Sigma(SFR) and Sigma(gas) in molecular cloud clumps, with some consistency in results among different models. However, due to uncertainties in input observables, it is not possible to accurately differentiate between the various models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Glen H. Hunter, Paul C. Clark, Simon C. O. Glover, Ralf S. Klessen
Summary: In this study, the impact of collision speed, magnetic field inclination, and resolution on the star formation rate (SFR) in cloud-cloud collisions is investigated. A factor of 2-3 increase in the SFR is found compared to no collision simulations, with high collisional velocities, parallel magnetic field and collision axis orientation, and lower resolution leading to earlier star formation. The alignment of velocity and magnetic field is consistent in low-density environments but becomes more perpendicular as density increases, indicating the compression of the magnetic field by collapsing gas.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
A. Avison, G. A. Fuller, N. Asabre Frimpong, S. Etoka, M. Hoare, B. M. Jones, N. Peretto, A. Traficante, F. van der Tak, J. E. Pineda, M. Beltran, F. Wyrowski, M. Thompson, S. Lumsden, Z. Nagy, T. Hill, S. Viti, F. Fontani, P. Schilke
Summary: The role of massive stars in shaping the interstellar medium in their host galaxy is significant. This study presents a sample of massive star-forming regions observed with ALMA and explores their fragmentation, clustering, and flux density properties. The sample contains multiple fragments per field, and the fragmentation scales are often larger than the thermal Jeans length. Furthermore, a tentative evolutionary trend is observed between the clump luminosity and the spectral line richness of the fields.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
J. Braine, Y. Sun, Y. Shimajiri, F. F. S. van der Tak, M. Fang, Ph. Andre, H. Chen, Y. Gao
Summary: In this study, maps and spectra of the HCN(1-0) and HCO+(1-0) lines in the extreme outer Galaxy were obtained using the Delingha telescope. The aim was to investigate the structure of molecular clouds in subsolar metallicity regions and their relation with star formation. The results showed that the HCN emission is optically thin and the HCO+ emission is stronger, indicating a low-density solution for the dense gas. The correlation between star formation and dense gas was found to be poor.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Guang-Xing Li, Xun Shi
Summary: Research shows that the gravitational interaction between compact objects passing through molecular clouds and the ambient gas can lead to the formation of thin and collimated features made of dense gas, known as 'molecular contrails'. The width of these contrails is determined by the mass and velocity of the compact object as well as the velocity dispersion of the ambient molecular medium. This study highlights a previously overlooked channel where stars and gas in the Galactic disc interact to form structures, and also presents a potential method for detecting dark compact objects in the Milky Way.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
P. A. B. Galli, H. Bouy, J. Olivares, N. Miret-Roig, L. M. Sarro, D. Barrado, A. Berihuete, E. Bertin, J-C Cuillandre
Summary: This study uses the second data release of the Gaia space mission to expand the census of stars in the Chamaeleon clouds and revisit the properties of the stellar populations associated with Chamaeleon I and Chamaeleon II dark clouds. The research identifies 188 and 41 high-probability members in Cha I and Cha II, respectively, revealing differences in distance between the subgroups of Cha I and a higher proportion of disc-bearing stars in Cha II.
ASTRONOMY & ASTROPHYSICS
(2021)
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
Hannah E. Ambrose, Yancy L. Shirley, Samantha Scibelli
Summary: Recent observations show that organic molecules are common in starless and pre-stellar cores, and deuterated organic molecules have not been well studied during the starless phase. An investigation of deuterated methanol towards 12 cores in the Taurus molecular cloud region indicates that deuterium fractionation of organic molecules during the starless phase might be more easily detectable than previously thought.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Zhiyuan Ren, Lei Zhu, Hui Shi, Nannan Yue, Di Li, Qizhou Zhang, Diego Mardones, Jingwen Wu, Sihan Jiao, Shu Liu, Gan Luo, Jinjin Xie, Chao Zhang, Xuefang Xu
Summary: The study of filamentary structures in the Orion A molecular cloud region OMC-3 MMS-7 using ALMA and SMA observations revealed close associations with star-forming cores. The analysis of N2H+ emission showed dense filaments intersecting at the central core MMS-7, indicating an inward motion towards pre-stellar core formation. This filament contraction may lead to the generation of intermediate-mass or high-mass stars, with a steady and less intense process compared to global spherical collapses.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Nirmit Sakre, Asao Habe, Alex R. Pettitt, Takashi Okamoto, Rei Enokiya, Yasuo Fukui, Takashi Hosokawa
Summary: In this study, the effects of magnetic fields on the formation of massive, self-gravitationally bound cores (MBCs) in high-speed cloud-cloud collisions (CCCs) are investigated through magnetohydrodynamic simulations. The results show that magnetic fields hinder the growth of cores, especially in short-duration collisions. This two-fold effect of magnetic fields on the MBC formation in CCCs results in a maximum collision speed for the formation of massive stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)