论文标题
Artemis模拟：银河系质量星系的恒星光环
The ARTEMIS simulations: stellar haloes of Milky Way-mass galaxies
论文作者
论文摘要
我们介绍了Artemis模拟，这是一组新的42个放大，高分辨率（Baryon颗粒质量约为2x10^4 MSUN/H），对位于银河系质量光环中的星系的流体动力学模拟模拟，并使用带有重新计算出的Stellar Seltar Refface的EATGLE Galaxy地层代码进行模拟。在这项研究中，我们分析了恒星光环的结构，特别是质量密度，表面亮度，金属性，颜色和年龄径向谱，通常与最近观察到局部星系的观察结果非常吻合。恒星密度轮廓非常适合断裂的功率定律，内部斜率为〜 -3，外部斜率为〜 -4，而断裂半径通常约为20-40 kpc。断裂半径通常标志着光环的原位形成与积聚驱动的形成之间的过渡。金属性，颜色和年龄剖面显示出温和的大规模梯度，尤其是当沿主要轴的球形平均或观察时。然而，沿着次要轴几乎是平坦的，与观测值一致。总体而言，结构特性可以通过两个因素来理解：原位恒星主导着内部区域，并且它们驻留在与光盘一致的空间框架分布中。因此，需要针对星系的主要和次要轴的观测值才能获得恒星光环的完整图片。
We introduce the ARTEMIS simulations, a new set of 42 zoomed-in, high-resolution (baryon particle mass of ~ 2x10^4 Msun/h), hydrodynamical simulations of galaxies residing in haloes of Milky Way mass, simulated with the EAGLE galaxy formation code with re-calibrated stellar feedback. In this study, we analyse the structure of stellar haloes, specifically the mass density, surface brightness, metallicity, colour and age radial profiles, finding generally very good agreement with recent observations of local galaxies. The stellar density profiles are well fitted by broken power laws, with inner slopes of ~ -3, outer slopes of ~ -4 and break radii that are typically ~ 20-40 kpc. The break radii generally mark the transition between in situ formation and accretion-driven formation of the halo. The metallicity, colour and age profiles show mild large-scale gradients, particularly when spherically-averaged or viewed along the major axes. Along the minor axes, however, the profiles are nearly flat, in agreement with observations. Overall, the structural properties can be understood by two factors: that in situ stars dominate the inner regions and that they reside in a spatially-flattened distribution that is aligned with the disc. Observations targeting both the major and minor axes of galaxies are thus required to obtain a complete picture of stellar haloes.
