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Main Authors: Fang, Guanwen, Zhu, Shiwei, Xu, Jun, Lu, Shiying, Zhou, Chichun, Dai, Yao, Lin, Zesen, Kong, Xu
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2512.15137
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author Fang, Guanwen
Zhu, Shiwei
Xu, Jun
Lu, Shiying
Zhou, Chichun
Dai, Yao
Lin, Zesen
Kong, Xu
author_facet Fang, Guanwen
Zhu, Shiwei
Xu, Jun
Lu, Shiying
Zhou, Chichun
Dai, Yao
Lin, Zesen
Kong, Xu
contents We present an enhanced unsupervised machine learning (UML) module within our previous \texttt{USmorph} classification framework featuring two components: (1) hierarchical feature extraction via a pre-trained ConvNeXt convolutional neural network (CNN) with transfer learning, and (2) nonlinear manifold learning using Uniform Manifold Approximation and Projection (UMAP) for topology-aware dimensionality reduction. This dual-stage design enables efficient knowledge transfer from large-scale visual datasets while preserving morphological pattern geometry through UMAP's neighborhood preservation. We apply the upgraded UML on I-band images of 99,806 COSMOS galaxies at redshift $0.2<z<1.2$ (to ensure rest-frame optical morphology) with $I_{\mathrm{mag}}<25$. The predefined cluster number is optimized to 20 (reduced from 50 in the original framework), achieving significant computational savings. The 20 algorithmically identified clusters are merged into five physical morphology types. About 51\% of galaxies (50,056) were successfully classified. To assess classification effectiveness, we tested morphological parameters for massive galaxies with $M_{*}>10^{9}~M_{\odot}$. Our classification results align well with galaxy evolution theory. This improved algorithm significantly enhances galaxy morphology classification efficiency, making it suitable for large-scale sky surveys such as those planned with the China Space Station Telescope (CSST).
format Preprint
id arxiv_https___arxiv_org_abs_2512_15137
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An updated efficient galaxy morphology classification model based on ConvNeXt encoding with UMAP dimensionality reduction
Fang, Guanwen
Zhu, Shiwei
Xu, Jun
Lu, Shiying
Zhou, Chichun
Dai, Yao
Lin, Zesen
Kong, Xu
Astrophysics of Galaxies
We present an enhanced unsupervised machine learning (UML) module within our previous \texttt{USmorph} classification framework featuring two components: (1) hierarchical feature extraction via a pre-trained ConvNeXt convolutional neural network (CNN) with transfer learning, and (2) nonlinear manifold learning using Uniform Manifold Approximation and Projection (UMAP) for topology-aware dimensionality reduction. This dual-stage design enables efficient knowledge transfer from large-scale visual datasets while preserving morphological pattern geometry through UMAP's neighborhood preservation. We apply the upgraded UML on I-band images of 99,806 COSMOS galaxies at redshift $0.2<z<1.2$ (to ensure rest-frame optical morphology) with $I_{\mathrm{mag}}<25$. The predefined cluster number is optimized to 20 (reduced from 50 in the original framework), achieving significant computational savings. The 20 algorithmically identified clusters are merged into five physical morphology types. About 51\% of galaxies (50,056) were successfully classified. To assess classification effectiveness, we tested morphological parameters for massive galaxies with $M_{*}>10^{9}~M_{\odot}$. Our classification results align well with galaxy evolution theory. This improved algorithm significantly enhances galaxy morphology classification efficiency, making it suitable for large-scale sky surveys such as those planned with the China Space Station Telescope (CSST).
title An updated efficient galaxy morphology classification model based on ConvNeXt encoding with UMAP dimensionality reduction
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2512.15137