Article
Astronomy & Astrophysics
Sajay Sunny Mathew, Christoph Federrath, Amit Seta
Summary: Turbulence is crucial for star formation, but its role in the initial mass function (IMF) is not fully understood. Magnetohydrodynamical simulations reveal that compressive turbulence driving produces a higher fraction of low-mass stars compared to solenoidal driving. The simulations capture the important features of the observed IMF form.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Henry B. Lane, Michael Y. Grudic, David Guszejnov, Stella S. R. Offner, Claude-Andre Faucher-Giguere, Anna L. Rosen
Summary: Simulating isolated giant molecular clouds is important for studying star formation dynamics, but the initial conditions of turbulence are uncertain. Researchers have developed a new simulation setup that combines advantages of previous methods and found that external driving can significantly suppress star formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Sajay Sunny Mathew, Christoph Federrath
Summary: The study demonstrates that various factors in star cluster formation, including protostellar outflows, affect the star formation rate, mass distribution, and initial mass function. The turbulence-based model and observational IMF agree well in the high-mass and low-mass regime, but do not predict any brown dwarfs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Vianey Camacho, Enrique Vazquez-Semadeni, Aina Palau, Manuel Zamora-Aviles
Summary: We conducted a numerical study on the balance of gravitational, kinetic, and magnetic energies in hub-filament structures within a giant molecular cloud. The study examined the scaling relationships between the virial parameter, Larson ratio, and mass and column density of the structures. We also compared our numerical results with an observational sample of massive clumps and found similar trends. The main controlling parameter of the energy budget in the structures is gravitational energy.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
James R. Beattie, Philip Mocz, Christoph Federrath, Ralf S. Klessen
Summary: The logarithmic density contrast of hydrodynamical supersonic turbulence exhibits significant non-Gaussian features that increase with the turbulent Mach number. By studying simulations with different driving modes, it is found that the non-Gaussian nature of the density contrast is more complicated than previously thought. The non-Gaussian features are present in highly magnetized plasma for low Mach numbers, but disappear for high Mach numbers.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
James R. Beattie, Mark R. Krumholz, Raphael Skalidis, Christoph Federrath, Amit Seta, Roland M. Crocker, Philip Mocz, Neco Kriel
Summary: Energy equipartition is a powerful theoretical tool in understanding astrophysical plasmas. This study explores the role of the magnetic coupling term between turbulent and large-scale fields. It is found that in sub-Alfvenic turbulence with a large-scale field, there is energy equipartition between the coupling term and the turbulent kinetic energy. Numerical simulations further support this conclusion and provide insights into the relation between turbulent mean field and total Alfven Mach numbers.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
James R. Beattie, Philip Mocz, Christoph Federrath, Ralf S. Klessen
Summary: This study develops an anisotropic model for density variance in molecular clouds, taking into account contributions from hydrodynamical and fast magnetosonic shocks. The model predicts an upper limit for density fluctuations in high Mach number conditions and shows good agreement with simulations. By considering sub-Alfvenic magnetic fields, the study provides insights into the bimodal overdensities observed in some molecular clouds and implications for star formation theory. Creating an anisotropic model for supersonic density fluctuations lays the groundwork for understanding star formation in highly anisotropic interstellar turbulence.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
James R. Beattie, Christoph Federrath, Neco Kriel, Philip Mocz, Amit Seta
Summary: The turbulent small-scale dynamo is likely the cause of the observed magnetization of the interstellar medium. This process converts kinetic energy into magnetic energy and can amplify and maintain a weak initial magnetic field. Through simulations, it has been found that the final saturated state of the turbulent dynamo is determined by the turbulence and plasma properties, regardless of the initial structure or amplitude of the magnetic field. This has implications for understanding and studying magnetic field maintenance in turbulent plasmas.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yue Hu, Christoph Federrath, Siyao Xu, Sajay Sunny Mathew
Summary: The interaction between turbulence, magnetic fields, self-gravity, and stellar feedback is crucial for understanding star formation. This study focuses on the effects of self-gravity and outflow feedback on the turbulent velocity within molecular clouds. The results show that outflow feedback can change the scaling of velocity fluctuations and amplify turbulence. Self-gravity and protostellar outflows increase velocity fluctuations and enhance fragmentation. The study also finds that self-gravity has a more significant effect on smaller dense clumps, while outflow feedback drives a higher fraction of solenoidal modes relative to compressive modes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
P. Mazumdar, F. Wyrowski, D. Colombo, J. S. Urquhart, M. A. Thompson, K. M. Menten
Summary: The feedback from the stellar cluster in G305 significantly impacts the excitation and dynamics of the giant molecular cloud. Areas with higher 8 μm flux exhibit higher median excitation temperatures, column densities, and (CO)-C-13 J = 3-2/2-1 ratios. Turbulence in the region is driven by strong stellar winds and regions with stronger feedback show distinct features in their velocity probability distribution functions.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Eric R. Moseley, R. Teyssier, B. T. Draine
Summary: This study investigates the stochastic acceleration mechanism of dust grains and demonstrates that they can be effectively accelerated to speeds beyond their shattering velocities. The implementation of novel magnetohydrodynamic particle-in-cell methods into the astrophysical fluid code RAMSES allows for the validation of the method under different physical conditions. The results provide insights into the protection of relatively pristine sub-micron pre-solar grains from significant wear.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Justin Kin Jun Hew, Christoph Federrath
Summary: This study presents novel 3D magnetohydrodynamic simulations of a laser-driven shock propagating into a stratified multiphase medium, investigating the post-shock turbulent magnetic field amplification via the turbulent dynamo mechanism. The results indicate that the growth rate of the magnetic field is consistent with the theoretical predictions for compressive turbulence driving in subsonic, compressible turbulence.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Andrea Bonilla-Barroso, Javier Ballesteros-Paredes, Jesus Hernandez, Luis Aguilar, Manuel Zamora-Aviles, Lee W. Hartmann, Aleksandra Kuznetsova, Vianey Camacho, Veronica Lora
Summary: Numerical simulations were used to study the formation and evolution of stellar clusters within molecular clouds. The results showed that the velocity dispersion of stars within collapsing cloud clumps remains constant regardless of their mass, while clusters formed in turbulence-dominated environments exhibit an inverse mass segregated velocity dispersion. The observations of the Orion Nebula Cluster suggested that it was formed by collapse within one free-fall time of its parental cloud. The study also addressed criticisms of models of collapsing star-forming regions and found that the observational and numerical data supported the idea of clusters forming through global, hierarchical, and chaotic collapse rather than being supported by turbulence.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Laura Ramirez-Galeano, Javier Ballesteros-Paredes, Rowan J. Smith, Vianey Camacho, Manuel Zamora-Aviles
Summary: Observational and theoretical evidence suggests that a significant portion of molecular clouds are unbound and dominated by turbulent motions. However, a more accurate calculation of the virial parameter, which takes into account not only self-gravity but also tidal stresses, reveals that a portion of the clouds are gravitationally bound but being torn apart by tides. These tidal forces primarily come from the molecular cloud complexes in which the clouds reside and possibly from massive young stellar complexes. Additionally, the results imply that interstellar turbulence may have a gravitational origin.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Rafael Zavala-Molina, Javier Ballesteros-Paredes, Adriana Gazol, Aina Palau
Summary: Recent studies propose the concept of tidal screening scenario, in which gravitationally unstable fragments near a protostar compete for gas reservoir in a star-forming clump. This contribution suggests incorporating the effect of external gravitational potential in the Jeans linear instability analysis. The research finds that an external gravitational potential can decrease the critical mass for perturbation collapse under compressive tidal forces, while increase it under disruptive tidal forces. The results provide new collapse conditions, equations for observers to determine if observed fragments can collapse, and equations to calculate fragmentation levels induced by collapse-induced turbulence.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
D. Seifried, S. Walch, S. Reissl, J. C. Ibanez-Mejia
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
P. R. Joshi, S. Walch, D. Seifried, S. C. O. Glover, S. D. Clarke, M. Weis
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
P. F. Rohde, S. Walch, D. Seifried, A. P. Whitworth, S. D. Clarke, D. A. Hubber
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
S. Haid, S. Walch, D. Seifried, R. Wunsch, F. Dinnbier, T. Naab
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
Jonathan Mackey, Stefanie Walch, Daniel Seifried, Simon C. O. Glover, Richard Wuensch, Felix Aharonian
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
Todor V. Veltchev, Philipp Girichidis, Sava Donkov, Nicola Schneider, Orlin Stanchev, Lyubov Marinkova, Daniel Seifried, Ralf S. Klessen
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
H. Beuther, Y. Wang, J. Soler, H. Linz, J. Henshaw, E. Vazquez-Semadeni, G. Gomez, S. Ragan, Th Henning, S. C. O. Glover, M. Y. Lee, R. Guesten
ASTRONOMY & ASTROPHYSICS
(2020)
Article
Astronomy & Astrophysics
Griselda Arroyo-Chavez, Enrique Vazquez-Semadeni
Summary: In this study, we investigated the origin of the observed scaling between the specific angular momentum and the radius of molecular clouds and their substructures, as well as the independence of the ratio of rotational to gravitational energy from the radius. By using a smoothed particle hydrodynamics simulation, we found that this relationship arises from a global tendency towards gravitational contraction mediated by angular momentum loss via turbulent viscosity, resulting in the fragmentation into low-angular momentum dense clumps and high-angular momentum diffuse envelopes.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Guido Granda-Munoz, Enrique Vazquez-Semadeni, Gilberto C. Gomez, Manuel Zamora-Aviles
Summary: The effect of numerical magnetic diffusion in magnetically supported molecular clouds is investigated. Simulations with low and intermediate resolutions collapse, while the simulation with the highest numerical resolution oscillates around an equilibrium state. By running current-sheet simulations and measuring the numerical magnetic diffusion coefficient, a criterion for the resolution of magnetic fields in MHD simulations is proposed.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Raul Naranjo-Romero, Enrique Vazquez-Semadeni, Robert M. Loughnane
Summary: This study presents a numerical investigation of the gravity-driven filamentary flow and finds that a stratified simulation can best match the observed density profiles. The flow changes direction smoothly without density divergence or shock development. The accretion from the filament to the core slows down the filament growth.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jesus M. Jaquez-Dominguez, Roberto Galvan-Madrid, Jacopo Fritz, Manuel Zamora-Aviles, Peter Camps, Gustavo Bruzual, Maarten Baes, Yuxin Lin, Enrique Vazquez-Semadeni
Summary: A direct comparison between hydrodynamical simulations and observations is necessary for improving the models and testing their biases. By applying the SKIRT radiative-transfer code to simulations of a star-forming cloud, and analyzing the synthetic observations using traditional methods, we found that additional interstellar radiation is necessary in the early stages of the simulation. The morphological evolution of the cloud continues for about 8 Myr due to the expansion of H ii regions and the creation of various structures.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Feng-Wei Xu, Ke Wang, Tie Liu, Paul F. Goldsmith, Qizhou Zhang, Mika Juvela, Hong-Li Liu, Sheng-Li Qin, Guang-Xing Li, Anandmayee Tej, Guido Garay, Leonardo Bronfman, Shanghuo Li, Yue-Fang Wu, Gilberto C. Gomez, Enrique Vazquez-Semadeni, Ken'ichi Tatematsu, Zhiyuan Ren, Yong Zhang, L. Viktor Toth, Xunchuan Liu, Nannan Yue, Siju Zhang, Tapas Baug, Namitha Issac, Amelia M. Stutz, Meizhu Liu, Gary A. Fuller, Mengyao Tang, Chao Zhang, Lokesh Dewangan, Chang Won Lee, Jianwen Zhou, Jinjin Xie, Wenyu Jiao, Chao Wang, Rong Liu, Qiuyi Luo, Archana Soam, Chakali Eswaraiah
Summary: In this study, ALMA Band-3/7 observations were conducted on the massive hub-filament system SDC335 to study its fragmentation and accretion processes. The observations revealed two massive dense cores, MM1 and MM2, along with their fragmentation and temperature estimation. Gas motion analysis showed the presence of four major gas streams connected to large-scale filaments, supporting continuous accretion and core feeding. The comprehensive study of SDC335 provides valuable insights into the gas kinematics of massive infalling clumps and calls for further systematic studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Vianey Camacho, Enrique Vazquez-Semadeni, Aina Palau, Manuel Zamora-Aviles
Summary: We conducted a numerical study on the balance of gravitational, kinetic, and magnetic energies in hub-filament structures within a giant molecular cloud. The study examined the scaling relationships between the virial parameter, Larson ratio, and mass and column density of the structures. We also compared our numerical results with an observational sample of massive clumps and found similar trends. The main controlling parameter of the energy budget in the structures is gravitational energy.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Ruben Guerrero-Gamboa, Enrique Vazquez-Semadeni
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Vianey Camacho, Enrique Vazquez-Semadeni, Aina Palau, Gemma Busquet, Manuel Zamora-Aviles
ASTROPHYSICAL JOURNAL
(2020)