论文标题
建立一个一致的框架，以比较观测和模拟中的星系合并
Towards a consistent framework of comparing galaxy mergers in observations and simulations
论文作者
论文摘要
目标。我们的目的是对观测值和模拟在低红移的质量依赖性上进行一致的比较，这是在空前的恒星质量上（10^9至10^12太阳能块）。 方法。我们首先对从下一代Illustris模拟（Illustristng）中选择的主要合并和非Mergers的理想合成图像进行了向前建模，以包括主要的观察效应。然后，我们使用模拟中的星系样本进行了逼真的模拟观察来训练深卷积神经网络（CNN）。随后，我们将受过训练的CNN应用于实际的Kilo-Agree调查（儿童）图像，从星系和大众组装（GAMA）调查中选择的星系图像。基于在观测和模拟中以一致的方式检测到的主要合并样品，我们确定了主要合并分数对Z左右0.15左右的恒星质量的依赖性，并在两者之间进行比较。 结果。 GAMA/儿童观察中检测到的主要合并部分的趋势相当温和，随着巨大质量在10^9 <m_sun <m_Star <m_star <10^11.5 m_sun中的恒星质量增加。在GAMA/儿童观察中，主要合并分数的质量依赖性和10^9.5 m_sun <m_star <m_star <10^10.5 m_sun的批量依赖性达成了很好的共识。但是，观察结果和模拟在M_STAR> 10^10.5M_SUN处显示出一些差异，这可能是由于模拟中其低核酸的超质量黑孔反馈在此质量尺度上导致淬火分数的急剧过渡。差异也可能是由于模拟的体积相对较小和/或在模拟和观测中测量恒星质量的差异。
Aims. We aim to perform consistent comparisons between observations and simulations on the mass dependence of the galaxy major merger fraction at low redshift over an unprecedentedly wide range of stellar masses (10^9 to 10^12 solar masses). Methods. We first carry out forward modelling of ideal synthetic images of major mergers and non-mergers selected from the Next Generation Illustris Simulations (IllustrisTNG) to include major observational effects. We then train deep convolutional neural networks (CNNs) using realistic mock observations of galaxy samples from the simulations. Subsequently, we apply the trained CNNs to real the Kilo-Degree Survey (KiDS) images of galaxies selected from the Galaxy And Mass Assembly (GAMA) survey. Based on the major merger samples, which are detected in a consistent manner in the observations and simulations, we determine the dependence of major merger fraction on stellar mass at z around 0.15 and make comparisons between the two. Results. The detected major merger fraction in the GAMA/KiDS observations has a fairly mild decreasing trend with increasing stellar mass over the mass range 10^9 < M_sun < M_star < 10^11.5 M_sun. There is good agreement in the mass dependence of the major merger fraction in the GAMA/KiDS observations and the IllustrisTNG simulations over 10^9.5 M_sun < M_star < 10^10.5 M_sun. However, the observations and the simulations show some differences at M_star > 10^10.5M_sun, possibly due to the supermassive blackhole feedback in its low-accretion state in the simulations which causes a sharp transition in the quenched fractions at this mass scale. The discrepancy could also be due to the relatively small volume of the simulations and/or differences in how stellar masses are measured in simulations and observations.
