The formation of massive molecular filaments and massive stars triggered by a magnetohydrodynamic shock wave

Abstract

Recent observations suggest that intensive molecular cloud collision can trigger massive star/cluster formation. The most important physical process caused by the collision is a shock compression. In this paper, the influence of a shock wave on the evolution of a molecular cloud is studied numerically by using isothermal magnetohydrodynamics (MHD) simulations with the effect of self-gravity. Adaptive-mesh-refinement and sink particle techniques are used to follow long-time evolution of the shocked cloud. We find that the shock compression of turbulent inhomogeneous molecular cloud creates massive filaments, which lie perpendicularly to the background magnetic field as we have pointed out in a previous paper. The massive filament shows global collapse along the filament, which feeds a sink particle located at the collapse center. We observe high accretion rateṀ acc > 10 −4 M sun yr −1 that is high enough to allow the formation of even O-type stars. The most massive sink particle achieves M > 50 M sun in a few times 10 5 yr after the onset of the filament collapse.

The JCMT BISTRO Survey: Magnetic Fields Associated with a Network of Filaments in NGC 1333

“…Although the dominant mechanisms for filament formation and evolution are still under debate, many theoretical studies and numerical simulations suggest that interstellar magnetic fields (B-fields, hereafter) may play a significant role (e.g., Nagai et al 1998;Kudoh & Basu 2008Nakamura & Li 2008;Vázquez-Semadeni et al 2011;Hennebelle 2013;Soler et al 2013;Klassen et al 2017;Inoue et al 2018). Dense clouds are formed through collisional interactions in the ISM and the associated shock-compressed fluid dynamics.…”

Effects of grain alignment efficiency on synthetic dust polarization observations of molecular clouds

“…On the one hand, it is possible that the numerical simulation models adopted in Paper I possess structures too distinct from those found in Vela C, which could account for the failures arising in the column density correlations, as column density is the most direct observation of gas structure. However, this objection may be countered by noting that the steep column density-polarization fraction correlation has been observed in many clouds, not just Vela C; presumably, the comparisons made in Paper I could be repeated with other clouds whose gas structures are significantly different from those in Vela C. Moreover, the models adopted in that work were based on plausible cloud formation scenarios (Inoue & Fukui 2013;Inoue et al 2018), and while idealized, it is unclear what characteristics other simulation paradigms (such as the turbulent periodic box) might alternatively select that would give rise to a correct anticorrelation. This situation may be clarified in future studies that might use a wider range of turbulent flow geometries in the simulations.…”

FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN): Molecular clouds toward W 33; possible evidence for a cloud–cloud collision triggering O star formation

“…They showed GMC collision enhanced star formation rate and efficiency (Wu et al 2017b). Inoue and Fukui (2013) studied the interface layer of the colliding clouds by three-dimensional MHD simulations, and showed formation of massive molecular cores, which likely lead to form high-mass protostars gaining high mass accretion rate helped by amplified turbulence and magnetic fields via supersonic collision ( see also Inoue et al 2017). Kobayashi et al (2017aKobayashi et al ( , 2017b discussed the evolution of GMC mass functions including cloud-cloud collisions.…”