Massive core/star formation triggered by cloud-cloud collision: Effect of magnetic field

Abstract

We study effect of magnetic field on massive dense core formation in colliding unequal molecular clouds by performing magnetohydrodynamic simulations with sub-parsec resolution (0.015 pc) that can resolve the molecular cores. Initial clouds with the typical gas density of the molecular clouds are immersed in various uniform magnetic fields. The turbulent magnetic fields in the clouds consistent with the observation by Crutcher et al. (2010) are generated by the internal turbulent gas motion before the collision, if the uniform magnetic field strength is 4.0 $\mu$G. The collision speed of 10 km s${}^{-1}$ is adopted, which is much larger than the sound speeds and the Alfvén speeds of the clouds. We identify gas clumps with gas densities greater than 5 $\times$ 10${}^{-20}$ g cm${}^{-3}$ as the dense cores and trace them throughout the simulations to investigate their mass evolution and gravitational boundness. We show that a greater number of massive, gravitationally bound cores are formed in the strong magnetic field (4.0 $\mu$G) models than the weak magnetic field (0.1 $\mu$G) models. This is partly because the strong magnetic field suppresses the spatial shifts of the shocked layer that should be caused by the nonlinear thin shell instability. The spatial shifts promote formation of low-mass dense cores in the weak magnetic field models. The strong magnetic fields also support low-mass dense cores against gravitational collapse. We show that the numbers of massive, gravitationally bound cores formed in the strong magnetic field models are much larger than the isolated, non-colliding cloud models, which are simulated for comparison. We discuss the implications of our numerical results on massive star formation.

arXiv commentPublished in PASJ (for special issue on cloud-cloud collision). This arXiv version is similar to the published paper ( https://academic.oup.com/pasj/article/doi/10.1093/pasj/psaa059/5867032 )

References in corpus (38)

• Toward Understanding Massive Star Formation
• A Multi-Code Analysis Toolkit for Astrophysical Simulation Data
• The Formation of Massive Stars from Turbulent Cores
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Enzo: An Adaptive Mesh Refinement Code for Astrophysics
• Re-examining Larson's Scaling Relationships in Galactic Molecular Clouds
• Magnetic Fields in Spiral Galaxies
• The Star Formation Rate of Supersonic MHD Turbulence
• Modeling Collapse and Accretion in Turbulent Gas Clouds: Implementation and Comparison of Sink Particles in AMR and SPH
• Star Formation Efficiencies and Lifetimes of Giant Molecular Clouds in the Milky Way
• Simulations of Pregalactic Structure Formation with Radiative Feedback
• Massive star formation in 100,000 years from turbulent and pressurized molecular clouds
• A new Jeans resolution criterion for (M)HD simulations of self-gravitating gas: Application to magnetic field amplification by gravity-driven turbulence
• Nonlinear Instabilities in Shock-Bounded Slabs
• On the Density Distribution in Star-forming Interstellar Clouds
• Formation of Massive Molecular Cloud Cores by Cloud-cloud Collision
• Turbulence and Magnetic Field Amplification in Supernova Remnants: Interactions Between A Strong Shock Wave and Multi-Phase Interstellar Medium
• Do cloud-cloud collisions trigger high-mass star formation? I. Small cloud collisions
• Molecular clouds towards RCW 49 and Westerlund 2; Evidence for cluster formation triggered by cloud-cloud collision
• Formation of Turbulent and Magnetized Molecular Clouds via Accretion Flows of HI Clouds
• Isolating signatures of major cloud-cloud collisions using position-velocity diagrams
• Formation of Magnetized Prestellar Cores with Ambipolar Diffusion and Turbulence
• Temperature and Density Distribution in the Molecular Gas Toward Westerlund 2: Further Evidence for Physical Association
• A new look at the molecular gas in M42 and M43; possible evidence for cloud-cloud collision which triggered formation of the OB stars in the Orion Nebula Cluster
• Triggered O star formation in M20 via cloud-cloud collision: Comparisons between high-resolution CO observations and simulations
• Isolating signatures of major cloud-cloud collisions II: The lifetimes of broad bridge features
• The Effect of the Interstellar Model on Star Formation Properties in Galactic Disks
• GMC Collisions as Triggers of Star Formation. III. Density and Magnetically Regulated Star Formation
• Anisotropic Formation of Magnetized Cores in Turbulent Clouds
• Formation of Massive, Dense Cores by Cloud-Cloud Collisions
• Magnetohydrostatic Equilibrium Structure and Mass of Filamentary Isothermal Cloud Threaded by Lateral Magnetic Field
• GMC Collisions as Triggers of Star Formation. II. 3D Turbulent, Magnetized Simulations
• A multi-wavelength study of star formation activity in the S235 complex
• Magnetic Field Amplification by Turbulence in A Relativistic Shock Propagating through An Inhomogeneous Medium
• Magnetized Non-linear Thin Shell Instability: Numerical Studies in 2D
• Molecular clouds toward three Spitzer bubbles S116, S117 and S118: Evidence for the cloud-cloud collision which formed the three \HII \ regions and a 10-pc scale molecular cavity
• The effect of photoionising feedback on star formation in isolated and colliding clouds
• Molecular Cloud Cores in the Galactic Center 50 $\mathrm{km}{\mathrm{s}}^{-1}$ Molecular Cloud

Cited by in corpus (13)

• Cloud-cloud collisions and triggered star formation
• The properties of clusters, and the orientation of magnetic fields relative to filaments, in magnetohydrodynamic simulations of colliding clouds
• ALMA Observations of Giant Molecular Clouds in M33. II. Triggered High-mass Star Formation by Multiple Gas Colliding Events at the NGC 604 Complex
• The Effect of Shock Wave Duration on Star Formation and the Initial Condition of Massive Cluster Formation
• New evidences in IRDC G333.73+0.37: colliding filamentary clouds, hub-filament system, and embedded cores
• Massive core/star formation triggered by cloud-cloud collision: II High-speed collisions of magnetized clouds
• Universal Properties of Dense Clumps in Magnetized Molecular Clouds Formed through Shock Compression of Two-phase Atomic Gases
• Impact of Radiation Feedback on the Formation of Globular Cluster Candidates during Cloud-Cloud Collisions
• Cloud-cloud collisions triggering star formation in galaxy simulations
• Giant molecular clouds and their Type classification in M74: Toward understanding star formation and cloud evolution
• Ionising feedback from an O star formed in a shock-compressed layer
• Gas and star kinematics in cloud-cloud collisions
• The influence of magnetic fields in Cloud-Cloud Collisions