The stellar metallicity distribution of disc galaxies and bulges in cosmological simulations The stellar MDF in galaxies
The stellar metallicity distribution of disc galaxies and bulges in cosmological simulations The stellar MDF in galaxies
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宇宙学模拟中盘状星系和核球的恒星金属丰度分布 星系中的恒星 MDF
DOI：
10.1111/j.1365-2966.2012.22052.x
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发表时间：
2012
影响因子：
4.8
通讯作者：
Calura F
中科院分区：
文献类型：
--
作者：
Calura F
通过对类银河盘星系的高分辨率宇宙流体动力学模拟，分析了其恒星金属丰度分布函数。在对每个模拟进行运动学分解成球体和圆盘子组件后，我们将预测的MDF与在太阳附近和银河系凸起中观察到的MDF进行比较。星星形成密度阈值的影响在星星形成历史中是可见的，这表明它们的行为受到阈值的驱动。导出的MDF显示的中值金属丰度低于0.2-0.3 dex比在盘和银河系凸起局部观察到的平均值。这种明显差异的可能原因包括使用低恒星产额和/或中心集中的星星形成。色散大于观察到的色散;这可能是由于模拟的盘相对于MW在运动学上更热。低金属量恒星的比例在很大程度上被高估了，从观测样本的负偏角可以看出。对于我们的基准MW类似物，我们研究了相对于那些通过吸积（从被破坏的卫星）形成的原位出生的恒星的金属丰度分布，并证明了这一低金属丰度的尾巴，主要是由吸积恒星。增强超新星和恒星辐射能量反馈到周围的星际介质的这些预破坏的卫星被建议作为一个重要的调节器的brackskewness。
By means of high-resolution cosmological hydrodynamical simulations of Milky Way (MW) like disc galaxies, we conduct an analysis of the associated stellar metallicity distribution functions (MDFs). After undertaking a kinematic decomposition of each simulation into spheroid and disc subcomponents, we compare the predicted MDFs to those observed in the solar neighbourhood and the Galactic bulge. The effects of the star formation density threshold are visible in the star formation histories, which show a modulation in their behaviour driven by the threshold. The derived MDFs show median metallicities lower by 0.2–0.3 dex than the MDF observed locally in the disc and in the Galactic bulge. Possible reasons for this apparent discrepancy include the use of low stellar yields and/or centrally concentrated star formation. The dispersions are larger than the one of the observed MDF; this could be due to simulated discs being kinematically hotter relative to the MW. The fraction of low-metallicity stars is largely overestimated, visible from the more negatively skewed MDF with respect to the observational sample. For our fiducial MW analogue, we study the metallicity distribution of the stars born in situ relative to those formed viaaccretion(from disrupted satellites), and demonstrate that this low-metallicity tail to the MDF is populated primarily by accreted stars. Enhanced supernova and stellar radiation energy feedback to the surrounding interstellar media of these pre-disrupted satellites is suggested as an important regulator of the MDF skewness.