Deblending Overlapping Galaxies in DECaLS Using Transformer-Based Algorithm: A Method Combining Multiple Bands and Data Types

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Main Authors: Zhang, Ran, Liu, Meng, Yi, Zhenping, Yuan, Hao, Yang, Zechao, Bu, Yude, Kong, Xiaoming, Jia, Chenglin, Bi, Yuchen, Zhang, Yusheng, Li, Nan
Format: Preprint
Published: 2025
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author Zhang, Ran
Liu, Meng
Yi, Zhenping
Yuan, Hao
Yang, Zechao
Bu, Yude
Kong, Xiaoming
Jia, Chenglin
Bi, Yuchen
Zhang, Yusheng
Li, Nan
author_facet Zhang, Ran
Liu, Meng
Yi, Zhenping
Yuan, Hao
Yang, Zechao
Bu, Yude
Kong, Xiaoming
Jia, Chenglin
Bi, Yuchen
Zhang, Yusheng
Li, Nan
contents In large-scale galaxy surveys, particularly deep ground-based photometric studies, galaxy blending is inevitable and poses a potential primary systematic uncertainty for upcoming surveys. Current deblenders predominantly rely on analytical modeling of galaxy profiles, facing limitations due to inflexible and imprecise models. We present a novel approach using a U-net structured transformer-based network for deblending astronomical images, which we term the CAT-deblender. It was trained using both RGB and grz-band images, spanning two distinct data formats from the Dark Energy Camera Legacy Survey (DECaLS) database, including galaxies with diverse morphologies. Our method requires only the approximate central coordinates of each target galaxy, bypassing assumptions on neighboring source counts. Post-deblending, our RGB images retain a high signal-to-noise peak, showing superior structural similarity to ground truth. For multi-band images, the ellipticity of central galaxies and median reconstruction error for the r-band consistently lie within +/-0.025 to +/-0.25, revealing minimal pixel residuals. In our comparison focused on flux recovery, our model shows a mere 1 percent error in magnitude recovery for quadruply blended galaxies, significantly outperforming SExtractor's higher error rate of 4.8 percent. By cross-matching with publicly accessible overlapping galaxy catalogs from the DECaLS database, we successfully deblended 433 overlapping galaxies. Furthermore, we demonstrated effective deblending of 63,733 blended galaxy images randomly selected from the DECaLS database.
format Preprint
id arxiv_https___arxiv_org_abs_2505_17452
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Deblending Overlapping Galaxies in DECaLS Using Transformer-Based Algorithm: A Method Combining Multiple Bands and Data Types
Zhang, Ran
Liu, Meng
Yi, Zhenping
Yuan, Hao
Yang, Zechao
Bu, Yude
Kong, Xiaoming
Jia, Chenglin
Bi, Yuchen
Zhang, Yusheng
Li, Nan
Astrophysics of Galaxies
In large-scale galaxy surveys, particularly deep ground-based photometric studies, galaxy blending is inevitable and poses a potential primary systematic uncertainty for upcoming surveys. Current deblenders predominantly rely on analytical modeling of galaxy profiles, facing limitations due to inflexible and imprecise models. We present a novel approach using a U-net structured transformer-based network for deblending astronomical images, which we term the CAT-deblender. It was trained using both RGB and grz-band images, spanning two distinct data formats from the Dark Energy Camera Legacy Survey (DECaLS) database, including galaxies with diverse morphologies. Our method requires only the approximate central coordinates of each target galaxy, bypassing assumptions on neighboring source counts. Post-deblending, our RGB images retain a high signal-to-noise peak, showing superior structural similarity to ground truth. For multi-band images, the ellipticity of central galaxies and median reconstruction error for the r-band consistently lie within +/-0.025 to +/-0.25, revealing minimal pixel residuals. In our comparison focused on flux recovery, our model shows a mere 1 percent error in magnitude recovery for quadruply blended galaxies, significantly outperforming SExtractor's higher error rate of 4.8 percent. By cross-matching with publicly accessible overlapping galaxy catalogs from the DECaLS database, we successfully deblended 433 overlapping galaxies. Furthermore, we demonstrated effective deblending of 63,733 blended galaxy images randomly selected from the DECaLS database.
title Deblending Overlapping Galaxies in DECaLS Using Transformer-Based Algorithm: A Method Combining Multiple Bands and Data Types
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2505.17452