Title: Exploring the connection between stellar halo profiles and accretion histories in $L_*$ galaxies Show Chinese title

Title: 探索$L_*$星系中恒星晕轮廓与吸积历史之间的联系

Abstract: I use a library of controlled minor merger N-body simulations, a particle tagging technique and Monte Carlo generated $\Lambda$CDM accretion histories to study the highly stochastic process of stellar deposition onto the accreted stellar halos (ASHs) of $L_*$ galaxies. I explore the main physical mechanisms that drive the connection between the accretion history and the density profile of the ASH. I find that: i) through dynamical friction, more massive satellites are more effective at delivering their stars deeper into the host; ii) as a consequence, ASHs feature a negative gradient between radius and the local mass-weighed virial satellite-to-host mass ratio; iii) in $L_*$ galaxies, most ASHs feature a density profile that steepens towards sharper logarithmic slopes at increasing radii, though with significant halo-to-halo scatter; iv) the ASHs with the largest total ex-situ mass are such because of the chance accretion of a small number of massive satellites (rather than of a large number of low-mass ones). Show Chinese abstract

Abstract: 我使用一个受控小合并N体模拟库、粒子标记技术以及蒙特卡罗生成的$\Lambda$冷暗物质吸积历史，来研究恒星沉积到$L_*$星系的吸积恒星晕(ASHs)上的高度随机过程。 我探索了驱动吸积历史与ASH密度轮廓之间联系的主要物理机制。 我发现：i) 通过动力摩擦，质量更大的卫星更有效地将其恒星带入宿主内部；ii) 因此，ASHs在半径和局部质量加权的虚拟卫星与宿主质量比之间呈现出负梯度；iii) 在$L_*$星系中，大多数ASHs的密度轮廓随着半径增加而变得更为陡峭，尽管存在显著的晕间差异；iv) 拥有最大总外源质量的ASHs是因为偶然吸积了一小部分大质量卫星（而不是大量低质量卫星）。