Elucidation of galactic magnetic field structure by pseudo-observation based on SPH simulation

Speaker: Yuta Tashima


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 has remained unclear parts. Since observables are integral values ​​along 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 simulation results. Our previous research adopted the galactic gaseous disk model calculated by MHD simulation, whose calculation assumed a static galactic stellar potential and ignored a cooling effect. Therefore, we thought more realistic results could be obtained using SPH simulation data that considers potential changes due to stellar motion. We calculated the magnetic field using the induction equation from the SPH simulation results and performed a pseudo-observation. As a result, we found that the magnetic field is strongly amplified around the wind blowing from the end of the bar. In the case of an edge-on view, pseudo-observation results can reproduce the X-shape structure often observed in edge-on starburst galaxies. However, the SPH case did not reproduce the magnetic spiral arm structure. This is because SPH solves the induction equation independently, and the result shows the importance of feedback to the motion of the magnetic field.