宇宙黎明期大质量星系中普遍存在的核盘与核棒
Ubiquitous nuclear disks and bars embedded in massive galaxies in the cosmic morning
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中文总结 AI 辅助
基于TNG50模拟中45个z=3大质量星系，发现其中心普遍为旋转支撑的核盘与核棒，而非核球，且此类结构在z≲1前不转为球状，表明无核球大质量星系是常见演化结果。
中文摘要 AI 辅助
高红移星系中心区域形态的研究仍相对不足，而近期的案例研究表明，巨盘可以在未先形成显著的中心球状结构的情况下出现。在此，我们利用TNG50模拟，研究了一个质量完备的样本——红移$z=3$处的45个大质量星系——的内部结构。通过双Sérsic轮廓分解、等密度椭圆拟合、内禀三维形状测量以及恒星动力学分析，我们发现这些中心结构普遍呈扁平状且由旋转支撑，其Sérsic指数较低（$n \lesssim 1$）。这表明中心区域主要是核盘和核棒，而非核球。追踪其演化，我们展示了这些核盘和核棒在富气体压实过程中出现，并且直到$z \lesssim 1$之前不会转变为球状且由速度弥散主导的系统，而在此之前，延展的恒星盘已经形成。我们的结果表明，大质量盘可以围绕旋转支撑的中心组装，且缺乏核球的大质量星系可能是星系演化的常见结果。
英文摘要
The morphology of the central regions of high-redshift galaxies remains relatively unexplored, while recent case studies suggest that giant disks can emerge without first developing a prominent central spheroid. Here, we investigate the inner structures of a mass-complete sample of 45 massive galaxies at $z=3$ in the TNG50 simulation. Through double-Sérsic profile decomposition, isodensity ellipse fitting, intrinsic three-dimensional shape measurements, and stellar kinematics, we find that these central structures are ubiquitously flattened and rotation-supported with low Sérsic indices ($n \lesssim 1$). This indicates that the central regions are predominantly nuclear disks and bars rather than bulges. Tracking their evolution, we show that these nuclear disks and bars emerge during gas-rich compaction and do not transform into spheroidal and dispersion-dominated systems until $z \lesssim 1$, before which extended stellar disks have already developed. Our results suggest that massive disks can assemble around rotation-supported centers and bulge-deficient massive galaxies may be a common outcome of galaxy evolution.
发表机构
- Peking University（北京大学）
- Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）
- Department of Astronomy, University of Michigan（密歇根大学天文学系）
- Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo（东京大学宇宙物质量子研究世界前沿中心（WPI））
- Department of Physics, Universita degli Studi di Milano-Bicocca（米兰比可卡大学物理系）
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