Photometric redshift estimation for emission line galaxies of DESI Legacy Imaging Surveys by CNN-MLP

作者：S. L. Wei, Changhua Li, Yanxia Zhang, Chenzhou Cui, Chao Tang, Jingyi Zhang, Yongheng Zhao, Xue-Bing Wu, Yihan Tao, Dongwei Fan, Shanshan Li, Yunfei Xu, Maoyuan Huang, Xing-Yu Yang, Zihan Kang, Jinghang Shi · 发表于：Publications of the Astronomical Society of Australia · 年份：2025 · DOI：10.1017/pasa.2025.10056 · 被引用次数：4 · 研究领域：Astronomical Observations and Instrumentation、Astronomy and Astrophysical Research、CCD and CMOS Imaging Sensors

Abstract Emission line galaxies (ELGs) are crucial for cosmological studies, particularly in understanding the large-scale structure of the Universe and the role of dark energy. ELGs form an essential component of the target catalogue for the Dark Energy Spectroscopic Instrument (DESI), a major astronomical survey. However, the accurate selection of ELGs for such surveys is challenging due to the inherent uncertainties in determining their redshifts with photometric data. In order to improve the accuracy of photometric redshift estimation for ELGs, we propose a novel approach CNN–MLP that combines convolutional neural networks (CNNs) with multilayer perceptrons (MLPs). This approach integrates both images and photometric data derived from the DESI Legacy Imaging Surveys Data Release 10. By leveraging the complementary strengths of CNNs (for image data processing) and MLPs (for photometric feature integration), the CNN–MLP model achieves a $\sigma_{\mathrm{NMAD}}$ (normalised median absolute deviation) of 0.0140 and an outlier fraction of 2.57%. Compared to other models, CNN–MLP demonstrates a significant improvement in the accuracy of ELG photometric redshift estimation, which directly benefits the target selection process for DESI. In addition, we explore the photometric redshifts of different galaxy types (Starforming, Starburst, AGN, and Broadline). Furthermore, this approach will contribute to more reliable photometric redshift estimation in ongoing and future large-scale...