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Accepted manuscript

Deblending overlapping galaxies in DECaLS using Transformer-Based algorithm: a method combining multiple bands and data types

Published online by Cambridge University Press:  19 March 2024

Ran Zhang
Affiliation:
School of Mechanical, Electrical and Information Engineering, Shandong University 180 Wenhua Xilu, Weihai 264209, Shandong, China
Meng Liu*
Affiliation:
School of Mechanical, Electrical and Information Engineering, Shandong University 180 Wenhua Xilu, Weihai 264209, Shandong, China
Zhenping Yi
Affiliation:
School of Mechanical, Electrical and Information Engineering, Shandong University 180 Wenhua Xilu, Weihai 264209, Shandong, China
Hao Yuan
Affiliation:
School of Mechanical, Electrical and Information Engineering, Shandong University 180 Wenhua Xilu, Weihai 264209, Shandong, China
Zechao Yang
Affiliation:
School of Mechanical, Electrical and Information Engineering, Shandong University 180 Wenhua Xilu, Weihai 264209, Shandong, China
Yude Bu
Affiliation:
School of Mathematics and Statistics, Shandong University 180 Wenhua Xilu, Weihai, 264209, Shandong, China
Xiaoming Kong
Affiliation:
School of Mechanical, Electrical and Information Engineering, Shandong University 180 Wenhua Xilu, Weihai 264209, Shandong, China
Chenglin Jia
Affiliation:
School of Mechanical, Electrical and Information Engineering, Shandong University 180 Wenhua Xilu, Weihai 264209, Shandong, China
Yuchen Bi
Affiliation:
School of Mechanical, Electrical and Information Engineering, Shandong University 180 Wenhua Xilu, Weihai 264209, Shandong, China
Yusheng Zhang
Affiliation:
School of Mechanical, Electrical and Information Engineering, Shandong University 180 Wenhua Xilu, Weihai 264209, Shandong, China
*
Author for correspondence: Meng Liu, Email: liumeng@sdu.edu.cn.

Abstract

In large-scale galaxy surveys, particularly deep ground-based photometric studies, galaxy blending was inevitable. Such blending posed a potential primary systematic uncertainty for upcoming surveys. Current deblenders predominantly depended on analytical modeling of galaxy profiles, facing limitations due to inflexible and imprecise models. We presented 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 the grz-band images, spanning two distinct data formats present in the Dark Energy Camera Legacy Survey (DECaLS) database, including galaxies with diverse morphologies in the training dataset. Our method necessitated only the approximate central coordinates of each target galaxy, sourced from galaxy detection, bypassing assumptions on neighboring source counts. Post-deblending, our RGB images retained a high signal-to-noise peak, consistently showing superior structural similarity against ground truth. For multi-band images, the ellipticity of central galaxies and median reconstruction error for r-band consistently lie within ±0.025 to ±0.25, revealing minimal pixel residuals. In our comparison of deblending capabilities focused on flux recovery, our model showed a mere 1% error in magnitude recovery for quadruply blended galaxies, significantly outperforming SExtractor’s higher error rate of 4.8%. Furthermore, by cross-matching with the publicly accessible overlapping galaxy catalogs from the DECaLS database, we successfully deblended 433 overlapping galaxies. Moreover, we’ve demonstrated effective deblending of 63,733 blended galaxy images, randomly chosen from the DECaLS database.

Type
Research Article
Copyright
© The Author(s), 2024. Published by Cambridge University Press on behalf of the Astronomical Society of Australia

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