Pseudo-observation of spiral galaxies focusing on depolarization based on MHD simulation
speaker: Yuta Tashima
Abstract:
It is known that the average magnetic field strength of spiral galaxies is about a few micro G, but the structure of the global field is still unknown. Since observables are integral values on the line of sight, it is difficult to obtain a three-dimensional structure. Therefore, we aim to clarify the relationship between the radiation field and the spatial distribution of physical quantities through pseudo-observations using global three-dimensional magnetohydrodynamics (MHD) simulation results. In particular, we are focusing on the depolarization effect, which is important in the meter-wave band, to verify the polarization model and to identify the emission region. As a result, we found that the spiral polarization projected on the screen is made up of overlapping magnetic flux tubes of different heights from the equatorial plane. It suggests that the traditional classification of global magnetic fields has difficulty reproducing the global structure of the magnetic fields. In addition, we have examined the possibility of separating this magnetic tube using the properties of beam depolarization. I will also report on this result.