J/ApJS/279/52 Ring galaxies from DESI Legacy Imaging Surveys DR9 (Zhang+, 2025)
Identifying ring galaxies in DESI Legacy Imaging Surveys using Machine Learning
methods.
Zhang A., Kong X., Liu B., Li N., Bu Y., Yi Z., Liu M.
<Astrophys. J. Suppl. Ser., 279, 52 (2025)>
=2025ApJS..279...52Z 2025ApJS..279...52Z
ADC_Keywords: Galaxies, optical; Redshifts; Photometry, ugriz
Keywords: Galaxies ; Ring galaxies ; Galaxy evolution ; Astronomy data analysis
Abstract:
The formation and evolution of ring structures in galaxies are crucial
for understanding the nature and distribution of dark matter, galactic
interactions, and the internal secular evolution of galaxies. However,
the limited number of existing ring galaxy catalogs has constrained
deeper exploration in this field. To address this gap, we introduce a
two-stage binary classification model based on the Swin Transformer
architecture to identify ring galaxies from the DESI Legacy Imaging
Surveys. This model first selects potential candidates and then
refines them in a second stage to improve classification accuracy.
During model training, we investigated the impact of imbalanced data
sets on the performance of the two-stage model. We experimented with
various model combinations applied to the data sets of the DESI Legacy
Imaging Surveys DR9, processing a total of 573,668 images with
redshifts ranging from z_spec=0.01-0.20 and magr<17.5. After
applying the two-stage filtering and conducting visual inspections,
the overall precision of the models exceeded 64.87%, successfully
identifying a total of 8052 newly discovered ring galaxies. With our
catalog, the forthcoming spectroscopic data from DESI will facilitate
a more comprehensive investigation into the formation and evolution of
ring galaxies.
Description:
The DESI Legacy Imaging Surveys (Dey+ 2019AJ....157..168D 2019AJ....157..168D) is a
comprehensive astronomical survey resulting from the collaboration of
three major public projects: the DECam Legacy Survey (DECaLS), the
Beijing-Arizona Sky Survey (BASS), and the Mayall z-band Legacy Survey
(MzLS). The DESI Legacy Imaging Surveys cover approximately 14000deg2
of the extragalactic sky visible from the Northern Hemisphere,
utilizing three key optical bands (g, r, and z). All images used in
this study are sourced from the DESI Legacy Imaging Surveys DR9.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 68 8052 Information on the 8052 ring galaxies identified in
this study
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See also:
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
VII/292 : DESI Legacy Imaging Surveys DR8 photometric redshifts (Duncan, 2022)
J/ApJS/181/572 : Collisional ring galaxies atlas (Madore+, 2009)
J/ApJS/186/427 : Detailed morphology of SDSS galaxies (Nair+, 2010)
J/MNRAS/461/3663 : Galaxy Zoo 2: new classification (Hart+, 2016)
J/MNRAS/477/894 : SDSS galaxies classification (Abraham+, 2018)
J/MNRAS/491/3767 : Automatic detection of ring galaxies in SDSS (Shamir+, 2020)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Release [9010/9012] DESI Legacy Imaging Surveys DR9
Camera and filter set identifier
6- 11 I6 --- Brickid [100968/633887] DESI Legacy Imaging Surveys
DR9 Brick ID
13- 17 I5 --- ObjID [25/11166] DESI Legacy Imaging Surveys DR9
catalog object number within the given brick
19- 27 F9.5 deg RAdeg Right Ascension (J2000)
29- 37 F9.5 deg DEdeg [-44/66.3] Declination (J2000)
39- 44 F6.4 --- z [0.01/0.2] Spectroscopic redshift (1)
46- 52 F7.1 3.63uJy gFlux [28.7/9855] DESI Legacy Imaging Surveys DR9 g
band model flux, in nanomaggy units (2)
54- 60 F7.1 3.63uJy rFlux [100/21406] DESI Legacy Imaging Surveys DR9 r
band model flux, in nanomaggy units (2)
62- 68 F7.1 3.63uJy zFlux [150.6/38693] DESI Legacy Imaging Surveys DR9
z band model flux, in nanomaggy units (2)
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Note (1): As provided by Zhou+ 2023JCAP...11..097Z 2023JCAP...11..097Z ;
DOI: 10.1088/1475-7516/2023/11/097
Note (2): In units of nanomaggies where a "maggy" is the flux f of the source
relative to the standard source f0 (which defines the zeropoint of
the magnitude scale). The standard source for each SDSS band is close
to but not exactly the AB source (3631Jy), meaning that a nanomaggy is
approximately 3.631x10-6Jy. See
https://www.sdss3.org/dr8/algorithms/magnitudes.php for full details.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Feb-2026