The importance of the magnetic field for a spiral arm formation in spiral galaxies and its visualization of the pseudo-observation

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K03916
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 16010:Astronomy-related
• Research Institution: National Astronomical Observatory of Japan (2020-2022); Kyushu University (2019)
• Principal Investigator: Machida Mami 国立天文台, 科学研究部, 准教授 (50455200)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 銀河磁場 / 磁気流体シミュレーション / 電波観測

Outline of Final Research Achievements

Galactic magnetic fields have average strengths of several to several tens of microgauss and have energies comparable to the pressure of galaxies and cosmic ray pressure. As such, they play various roles in the formation of star forming regions, the generation of galactic winds, and the acceleration and orbital bending of cosmic ray particles. To identify the polarization of the cosmic background radiation, it is necessary to know the details of the magnetic field structure of the Milky Way Galaxy. Therefore, we performed numerical simulations and pseudo-observations using the numerical results to reveal the magnetic field structure and how it is observed in spiral magnetic fields of galaxies, including the Milky Way. As a result, we found that the spiral magnetic field structures inferred from the polarization data projected onto the celestial plane are sometimes not spatially connected, and we developed a new method to separate them for separate them.

Free Research Field

宇宙物理

Academic Significance and Societal Importance of the Research Achievements

銀河ガス円盤の3次元磁気流体数値実験に基づいた擬似観測を行い、天球面上に射影された観測結果は、実際の3次元分布の中でどの領域の寄与が重要かなどを明らかにした。また、センチ波からメートル波帯の複数のバンドの観測結果、偏波強度分布から視線方向に積分された観測量から3次元構造を分離する新しい手法を提案した。現在、センチ波・メートル波の新しい電波干渉計が稼働を始めており、また、2020年代後半にはさらに大型なSquare Killometre Array phase 1(SKA1)が稼働を開始する。これらの観測結果が実際に排出される前に、データ解釈の理論的な補強を行った。