2016/06/16 by Zamora-Avilés Manuel, Vázquez-Semadeni Enrique, Manuel, Zamora-Avilés +6 · 1 citation
Physics and Astronomy · #Astrophysics and Star Formation Studies #Astro and Planetary Science #Solar and Space Plasma Dynamics
paper · pdf · doi:10.48550/arxiv.1606.05343
We present magnetohydrodynamic simulations aimed at studying the effect of\nthe magnetic suppression of turbulence (generated through various instabilities\nduring the formation of molecular clouds by converging) on the subsequent star\nformation (SF) activity. We study four magnetically supercritical models with\nmagnetic field strengths B= 0, 1, 2, and 3 \μG (corresponding to\nmass--to--flux ratios of \∞, 4.76, 2.38, and 1.59 times the critical\nvalue), with the magnetic field, initially being aligned with the flows. We\nfind that, for increasing magnetic field strength, the clouds formed tend to be\nmore massive, denser, less turbulent, and with higher SF activity. This causes\nthe onset of star formation activity in the non--magnetic or more weakly\nmagnetized cases to be delayed by a few Myr in comparison to the more strongly\nmagnetized cases. We attribute this behavior to the suppression of the\nnonlinear thin shell instability (NTSI) by the magnetic field, previously found\nby Heitsch and coworkers. This result is contrary to the standard notion that\nthe magnetic field provides support to the clouds, thus reducing their star\nformation rate (SFR). However, our result is a completely nonlinear one, and\ncould not be foreseen from simple linear considerations.\n