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arXiv 2007.00039astro-ph.GAastro-ph.IM
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宇宙学模拟中精细星系恒星形态与恒星形成活动之间的关系:深度学习观点

The relationship between fine galaxy stellar morphology and star formation activity in cosmological simulations: a deep learning view

Lorenzo Zanisi, Marc Huertas-Company, Francois Lanusse, Connor Bottrell, Annalisa Pillepich, Dylan Nelson, Vicente Rodriguez-Gomez, Francesco Shankar, Lars Hern… 展开作者

Lorenzo Zanisi, Marc Huertas-Company, Francois Lanusse, Connor Bottrell, Annalisa Pillepich, Dylan Nelson, Vicente Rodriguez-Gomez, Francesco Shankar, Lars Hernquist, Avishai Dekel, Berta Margalef-Bentabol, Mark Vogelsberger, Joel Primack

摘要:

星系形成和演化的流体动力学模拟试图完全模拟塑造星系的物理过程。模拟星系形态与真实星系形态之间的一致性,以及形态类型在星系尺度关系中的分布方式,是我们对星系形成物理知识的重要探索。在这里,我们提出了一种无监督的深度学习方法,对来自Illustris和IllustrisTNG(TNG 100和TNG 50)模拟的星系的精细形态结构进行严格的测试,以对抗斯隆数字巡天的子样本观测。我们的框架基于PixelCNN,这是一种具有显式似然性的图像生成自回归模型。我们采用了一种策略,将两个PixelCNN网络的输出结合在一个度量中,该度量将星系的精细形态细节与天空背景隔离开来。我们能够通过\emph{quantitatively}确定IllustrisTNG的改进,特别是在高分辨率TNG 50运行中,超过原始的Illustris。然而,我们发现,星系结构的细节仍然是不同的观测和模拟的星系。这种差异是由小的,更球状的,淬灭的星系,这是全球不太准确,无论分辨率和经历了三个模拟探索之间的改善不大。我们推测,这种分歧,这是不太严重的淬火盘状星系,可能源于一个仍然太粗糙的数值分辨率,这很难正确地捕捉内部,致密的淬火球状星系的区域。

英文摘要:

Hydrodynamical simulations of galaxy formation and evolution attempt to fully model the physics that shapes galaxies. The agreement between the morphology of simulated and real galaxies, and the way the morphological types are distributed across galaxy scaling relations are important probes of our knowledge of galaxy formation physics. Here we propose an unsupervised deep learning approach to perform a stringent test of the fine morphological structure of galaxies coming from the Illustris and IllustrisTNG (TNG100 and TNG50) simulations against observations from a subsample of the Sloan Digital Sky Survey. Our framework is based on PixelCNN, an autoregressive model for image generation with an explicit likelihood. We adopt a strategy that combines the output of two PixelCNN networks in a metric that isolates the fine morphological details of galaxies from the sky background. We are able to \emph{quantitatively} identify the improvements of IllustrisTNG, particularly in the high-resolution TNG50 run, over the original Illustris. However, we find that the fine details of galaxy structure are still different between observed and simulated galaxies. This difference is driven by small, more spheroidal, and quenched galaxies which are globally less accurate regardless of resolution and which have experienced little improvement between the three simulations explored. We speculate that this disagreement, that is less severe for quenched disky galaxies, may stem from a still too coarse numerical resolution, which struggles to properly capture the inner, dense regions of quenched spheroidal galaxies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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