标题： 磁场对球状星团中第二代恒星形成的影响 显示英文标题

标题： The Influence of Magnetic Fields on Second-Generation Star Formation in Globular Clusters

摘要： 我们使用三维辐射磁流体动力学模拟，研究了磁场在原球状星团（GC）中第二代（SG）恒星形成中的先前未被探索的作用。 本研究基于渐近巨星分支（AGB）情景，并包含了来自AGB恒星的光致电离反馈和恒星风。 我们在一个年轻的（$34$Myr）大质量（$10^6 $Msun）原球状星团中模拟SG的形成，该星团穿过一个磁化的、均匀的星际介质。 我们的结果表明，磁场强度和方向的变化显著影响星团周围的气体几何结构和SG恒星形成区域。 总体而言，磁场将SG的形成限制在星团的极中心区域，更强的磁场倾向于形成更紧凑的SG星团。 对于磁场强度为$0.5$和$5$微高斯的情况，我们观察到形成的SG恒星的质量没有显著变化。 然而，当存在强$50$微高斯磁场时，我们看到总SG质量增加了$25$百分比或减少了$70$百分比，分别对应于磁场与星团运动平行或垂直的情况。 这种变化反映了磁场如何影响气体吸积，因为我们的结果表明，除了强垂直磁场的情况外，从星际介质（ISM）吸积的气体略微占主导地位，此时气体吸积被有效抑制。 此外，更强的磁场限制了星团保留其抛射物的能力，导致形成氦丰度较低的恒星。 另一方面，强垂直磁场产生了起源于AGB抛射物的SG恒星，并表现出最高的氦丰度。 显示英文摘要

摘要： We investigate the previously unexplored role of magnetic fields in the formation of second-generation (SG) stars in proto-globular clusters (GCs) using 3D radiation-magnetohydrodynamical simulations. This study is based on the asymptotic giant branch (AGB) scenario and incorporates photoionization feedback and stellar winds from AGB stars. We model SG formation within a young ($34$ Myr) massive ($10^6 $ Msun) proto-GC moving through a magnetized, homogeneous interstellar medium. Our results indicate that variations in magnetic field strength and orientation significantly influence the gas geometry and SG star-forming regions around the cluster. Overall, magnetic fields limit SG formation to the very center of the cluster, with stronger magnetic fields tending to form more compact SG clusters. For magnetic field strengths of $0.5$ and $5$ microG, we observe no substantial changes in the mass of formed SG stars. However, with a strong $50$ microG field, we see a $25$ percent increase or a $70$ percent decrease in total SG mass, for a field aligned parallel or perpendicular to the cluster's motion, respectively. This variation reflects how magnetic fields influence gas accretion, as our results suggest that gas accreted from the interstellar medium (ISM) slightly dominates over AGB ejecta in the cluster, except in cases of strong perpendicular fields, where gas accretion is efficiently suppressed. Additionally, stronger magnetic fields limit the cluster's ability to retain its ejecta, leading to the formation of stars with lower helium abundances. On the other hand, a strong perpendicular magnetic field produces SG stars that originate from AGB ejecta and exhibit the highest helium abundances.