论文标题

关于宇宙学模拟的星系簇的相空间结构

On the phase-space structure of galaxy clusters from cosmological simulations

论文作者

Marini, I., Saro, A., Borgani, S., Murante, G., Rasia, E., Dolag, K., Lin, W., Napolitano, N. R., Ragagnin, A., Tornatore, L., Wang, Y.

论文摘要

宇宙N体模拟是研究暗物质(DM)光环的形成和演化的绝佳工具,以及在宇宙中最大的质量尺度上产生通用概况的机制。特别是,速度分散$σ_\ mathrm {v} $与密度$ρ$的组合可以用来定义pseudo-entropy $ s(r)=σ_\ mathrm {v} $ s \ propto \,r^{\,α} $。我们分析了大规模星系簇的一组宇宙流体动力学重新模拟,并研究了模拟星系簇中不同无碰撞的组件所追踪的伪透镜曲线:DM,恒星和子结构。我们分析了四组模拟,探索了不同的分辨率和物理(N体和全流动动力学模拟),以研究收敛性和重子的影响。我们发现,重子显着影响了由子结构所追踪的伪透镜剖面的内部区域,而DM颗粒曲线的特征是几乎普遍的行为,因此表明伪透镜的水平可以代表潜在的低量表质量质量 - 质量质量。我们比较观察到的和模拟的伪内部轮廓,并在归一化和斜率上找到良好的一致性。但是,我们证明了用于得出观察到的伪内剖面的方法可能引入偏见并低估了合并的影响。最后,我们研究了恒星所追踪的伪内向,集中了我们对群内光(ICL)和与最明亮的聚类星系(BCG)结合的恒星之间的动力学区别的兴趣:这两个伪透镜的组合被一个单个动力划分的单个动力被单个动力划分了几乎整个Cluster virial girial girial girial girip civust virip。

Cosmological N-body simulations represent an excellent tool to study the formation and evolution of dark matter (DM) halos and the mechanisms that have originated the universal profile at the largest mass scales in the Universe. In particular, the combination of the velocity dispersion $σ_\mathrm{v}$ with the density $ρ$ can be used to define the pseudo-entropy $S(r)=σ_\mathrm{v}^2/ρ^{\,2/3}$, whose profile is well-described by a simple power-law $S\propto\,r^{\,α}$. We analyze a set of cosmological hydrodynamical re-simulations of massive galaxy clusters and study the pseudo-entropy profiles as traced by different collisionless components in simulated galaxy clusters: DM, stars, and substructures. We analyze four sets of simulations, exploring different resolution and physics (N-body and full hydrodynamical simulations) to investigate convergence and the impact of baryons. We find that baryons significantly affect the inner region of pseudo-entropy profiles as traced by substructures, while DM particles profiles are characterized by an almost universal behavior, thus suggesting that the level of pseudo-entropy could represent a potential low-scatter mass-proxy. We compare observed and simulated pseudo-entropy profiles and find good agreement in both normalization and slope. We demonstrate, however, that the method used to derive observed pseudo-entropy profiles could introduce biases and underestimate the impact of mergers. Finally, we investigate the pseudo-entropy traced by the stars focusing our interest in the dynamical distinction between intracluster light (ICL) and the stars bound to the brightest cluster galaxy (BCG): the combination of these two pseudo-entropy profiles is well-described by a single power-law out to almost the entire cluster virial radius.

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