Visit ASIAA Homepage Registration Deadline: August 15, 2019 (Taiwan Time)
Science with the Submillimeter Array: Present and Future
November 4(Mon)-5(Tue), 2019
ASIAA, Taipei, Taiwan

Poster Presentation

Magnetic fields in idealized isolated disk galaxies

Author(s): En Chen (JBCA)

Presenter: En Chen (Jodrell Bank Centre for Astrophysics (JBCA), University of Manchester)

Magnetic fields are a ubiquitous feature of the interstellar medium (ISM) in galaxies.However, it is still unclear if they play a dominant role in star formation or are asecondary effect. As part of our ”Cloud Factory” (Smith et al. 2019) suite of simulations we use the moving-mesh code AREPO to investigate how magnetic fields affect the formation of long filamentary clouds in spiral galaxies and the star formation within them. As initial conditions we consider toroidal seed field of (0.04, 0.2 and 1μG) and a poloidal seed field of 0.04μG as well as an non-magnetic run for comparison to explore a range of magnetizations. We find that the magnetic strength is quickly amplified by the differential rotation, eventually reaching a saturation value of ~10μG. Stronger seed field suppress the formation of galactic scale filaments due to the additional magnetic pressure. This leads to a lower star formation rate compared to simulations with weaker magnetic field. The magnetic field structure is significantly distorted by supernova feedback. The orientations of the magnetic field are aligned with the gas motion within the shell which was driven by supernova explosion, on the other hand, they turn to bend along inner rim of the shell. In addition, high speed streams (n>1cm−3andv>20km s−1)are also oriented parallel to the magnetic field. The relative orientation between the magnetic field and the filament changes from parallel to perpendicular with density and magnetization strength in agreement with observations such as those by the Planck collaboration.

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