J/A+A/694/A271 Attributes of DESI DR9 spiral galaxies (Cai+, 2025)
Parameter measurement based on photometric images.
I. The method and the gas-phase metallicity of spiral galaxies.
Cai J.-H., Li N., Yang H.-F., Wang L.-L., Zheng A.-Y., Hao J., Zhao X.,
Xun Y.
<Astron. Astrophys. 694, A271 (2025)>
=2025A&A...694A.271C 2025A&A...694A.271C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Galaxies, photometry ; Abundances
Keywords: methods: data analysis - methods: statistical - catalogs -
galaxies: abundances
Abstract:
The gas-phase metallicity is a crucial parameter for understanding the
evolution of galaxies. Considering that the number of multi-band
galaxy images can typically reach tens of millions, using these images
as input data for predicting gas-phase metallicity has become a
feasible method. However, the accuracy of metallicity estimates from
images is relatively limited. To solve this problem, we propose Galaxy
Parameter Measurement Residual Network (GPM-ResNet), a deep learning
method designed to predict gas-phase metallicity from photometric
images of DESI. The parameter of photometric images are labeled with
gas-phase metallicity values, which are obtained through spectroscopic
methods with high accuracy. These labeled images serve as the training
dataset for the GPM-ResNet method. GPM-ResNet mainly consists of two
modules: a multi-order feature extractor and a parameter generator,
enhancing the ability to effectively extract features related to
gas-phase metallicity from photometric images. The σ of
Zpred-Ztrue is 0.12dex, which significantly outperforms the predicted
results of the second-order polynomial (σ=0.16dex) and the
third-order polynomial (σ=0.16dex) fitted using the
color-metallicity relation on the same dataset. To further emphasize
the superiority of GPM-ResNet, we analyze the predicted results on
various network architectures, galaxy sizes, image resolutions, and
wavelength bands of images. Moreover, we explore the Mass-Metallicity
relation and recover the relation successfully by utilizing the
predicted values Zpred. Finally, we apply GPM-ResNet to predict the
gas-phase metallicity of spiral (EXP) galaxies observed by DESI,
resulting in a comprehensive catalog containing 5095815 data.
Description:
The catalog contains attributes of spiral galaxies (EXP) from the DESI
DR9 dataset. Parameters include Right Ascension (ra), Declination
(dec), camera and filter settings (release), brick sky position
(brickid), catalog object number within the brick (objid),
spectroscopic redshift (z_spec), photometric redshift (zphotmedian),
r-band apparent magnitude (mag_r), and predicted gas-phase metallicity
(Z_pred).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 95 5095815 Catalog of spiral galaxies (EXP) in DESI DR9
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See also:
VII/292 : DESI Legacy Imaging Surveys DR8 photometric redshifts (Duncan, 2022)
https://www.legacysurvey.org/dr9/description : DESI DR9 Home Page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension (J2000) (ra)
12- 21 F10.6 deg DEdeg Declination (J2000) (dec)
24- 27 I4 --- Release Camera and filter settings (release)
33- 40 F8.1 --- BrickId Brick sky position (brickid)
43- 49 F7.1 --- objId Catalog object number within the brick (objid)
52- 60 F9.5 --- zspec ?=-99 Spectroscopic redshift (z_spec)
63- 69 F7.5 --- zphotmed Photometric redshift (median) (zphotmedian)
78- 85 F8.5 mag rmag r-band apparent magnitude (mag_r)
88- 95 F8.5 --- Zpred Predicted gas-phase metallicity (Z_pred)
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History:
From Jiang-Hui Cai, Jianghui(at)tyust.edu.cn
Acknowledgements:
The work is supported by the National Natural Science Foundation of
China (Grant Nos. 12473105, 12473106, 62272336, 12273075), Projects of
Science and Technology Cooperation and Exchange of Shanxi Province
(Grant Nos. 202204041101037, 202204041101033), The central government
guides local funds for science and technology development
(YDZJSX2024D049), the science research grant from the China Manned
Space Project with No. CMS-CSST-2021- B03, and Guanghe Fund (No.
ghfund202407027490).
(End) Patricia Vannier [CDS] 09-Jan-2025