arXiv:2508.00049astro-ph.COastro-ph.IM2025-08

用视觉变压器精准分割暗物质原晕,性能远超传统方法。

Segmenting proto-halos with vision transformers

  • 采用视觉变压器替代传统CNN,提升原晕分割精度。
  • 对各质量类别的原晕,总质量分割误差低于1%。
  • 适合天文物理与深度学习交叉研究者阅读。

早期宇宙中微小的宇宙扰动演化形成暗物质晕,这一过程高度非线性,通常通过N体模拟建模。本文探索利用深度学习对初始密度场中的原晕区域进行分割和分类,以预测其在红移z=0时的最终晕质量。对比了基于V-Net设计的全卷积神经网络(CNN)与U-Net Transformer两种架构,发现基于变压器的模型在各项指标上均显著优于CNN,对每个晕类别的总分割质量误差低于1%。两者均大幅超越基于扰动理论的Pinocchio模型,尤其在低质量晕及原晕边界细节重建方面表现突出。还研究了密度场、潮汐剪切及其组合输入特征的影响。最后使用Grad-CAM生成CNN的类别激活热图,初步揭示了网络如何利用输入场信息。

原文摘要 · Abstract (English)

The formation of dark-matter halos from small cosmological perturbations generated in the early universe is a highly non-linear process typically modeled through N-body simulations. In this work, we explore the use of deep learning to segment and classify proto-halo regions in the initial density field according to their final halo mass at redshift z=0. We compare two architectures: a fully convolutional neural network (CNN) based on the V-Net design and a U-Net transformer. We find that the transformer-based network significantly outperforms the CNN across all metrics, achieving sub-percent error in the total segmented mass per halo class. Both networks deliver much higher accuracy than the perturbation-theory-based model \textsc{pinocchio}, especially at low halo masses and in the detailed reconstruction of proto-halo boundaries. We also investigate the impact of different input features by training models on the density field, the tidal shear, and their combination. Finally, we use Grad-CAM to generate class-activation heatmaps for the CNN, providing preliminary yet suggestive insights into how the network exploits the input fields.

暗物质视觉变压器图像分割天体物理

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