J/A+A/696/A130 Dwarf galaxy candidates detection (Yang+, 2025)
An automatic detection method of small size dwarf galaxy candidates.
Yang H.-F., Zhang B.-Y., Cai J.-H., Qu H., Zheng A.-Y., Hao J., Chen X.,
Zhao X., Xun Y.
<Astron. Astrophys. 696, A130 (2025)>
=2025A&A...696A.130Y 2025A&A...696A.130Y (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Galaxy catalogs ; Redshifts ; Photometry, SDSS
Keywords: methods: data analysis - techniques: image processing - survey -
galaxies: dwarf
Abstract:
The missing satellites problem remains a core issue of the {LAMBDA}CDM
model. On small-scale, the number of observed dwarf galaxies is still
fewer than the number predicted by existing theories. Therefore,
finding fainter dwarf galaxies in deeper images is crucial for
refining the existing theoretical framework. In this study, we propose
an end-to-end automatic identification scheme for small size and faint
dwarf galaxies based on DESI photometric images and provide a batch of
dwarf galaxy candidates. We develop a dwarf galaxy automatic detection
model, YOLO-DG, based on the YOLOv7 framework, achieving a precision
of 88.2% and a recall of 89.1% on the test set. We identify 742251
dwarf galaxy candidates across the entire DESI DR9 footprint using
YOLO-DG, with their spectral redshifts concentrated in the range of 0
to 0.1. The faintest dwarf galaxy candidates detected by YOLO-DG have
magnitudes of 31.61mag, 27.62mag, and 32.78mag in the g, r, and z
bands, respectively. We identify 95230 local volume dwarf galaxy
candidates, 33 of which are identified based on spectral redshift. The
half-light radius of the smallest local volume dwarf galaxy candidate
is 0.31 arcsec. Finally, we provide a complete catalog of local volume
dwarf galaxy candidates.
Description:
This catalog contains all the samples analyzed in our paper, including
local volume dwarf galaxy candidates, high-confidence sources in
subsequent analysis, and complete detection results.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
catalog1.dat 122 95197 Local volume dwarf galaxy candidates identified
based on photometric redshift
catalog2.dat 121 33 Local volume dwarf galaxy candidates identified
based on spectral redshift
catalog3.dat 55 650 Targets too faint to be clearly distinguished
by the naked eye
catalog4.dat 101 26 Targets that were clearly observed to be actual
astronomical object through visual inspection
but were not identified by DESI
catalog5.dat 101 746899 All sources detected by YOLO-DG
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Byte-by-byte Description of file: catalog1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Index Index
7- 26 A20 --- Name Unique name for each candidate based on
position, DHHMMSS.ss_DDMMSS.ss
28- 31 I4 --- release Camera and filter settings
36- 41 I6 --- brickid Brick ID
44- 51 A8 --- brickname Name of brick
54- 58 I5 --- objid Catalog object number within this brick
60- 67 F8.4 deg RAdeg Right ascension at equinox J2000
69- 76 F8.4 deg DEdeg Declination at equinox J2000
78- 82 F5.2 mag gmag g-band magnitude
84- 88 F5.2 mag rmag r-band magnitude
90- 94 F5.2 mag zmag ?=99 z-band magnitude
96-100 F5.2 arcsec rhl Half-light radius of galaxy model for
galaxy type
114-122 F9.6 --- zph Photometric redshift
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Byte-by-byte Description of file: catalog2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Index Index
7- 26 A20 --- Name Unique name for each candidate based on
position, DHHMMSS.ss_DDMMSS.ss
28- 31 I4 --- release Camera and filter settings
36- 41 I6 --- brickid Brick ID
44- 51 A8 --- brickname Name of brick
54- 58 I5 --- objid Catalog object number within this brick
60- 67 F8.4 deg RAdeg Right ascension at equinox J2000
69- 76 F8.4 deg DEdeg Declination at equinox J2000
78- 82 F5.2 mag gmag g-band magnitude
84- 88 F5.2 mag rmag r-band magnitude
90- 94 F5.2 mag zmag z-band magnitude
96-100 F5.2 arcsec rhl Half-light radius of galaxy model for
galaxy type
114-121 F8.6 --- z Spectral redshift
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Byte-by-byte Description of file: catalog3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.4 deg RAdeg Right ascension at equinox J2000 (1)
10- 17 F8.4 deg DEdeg Declination at equinox J2000 (1)
19- 26 F8.4 deg XWORLD Barycenter position along world x axis
28- 35 F8.4 deg YWORLD Barycenter position along world y axis
37- 43 F7.4 mag magAUTO Kron-like elliptical aperture magnitude
46- 55 F10.4 pix FluxRad Radius enclosing a specified
fraction of the flux
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Note (1): This position is obtained through model detection.
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Byte-by-byte Description of file: catalog4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.4 deg RAdeg Right ascension at equinox J2000 (1)
10- 17 F8.4 deg DEdeg Declination at equinox J2000 (1)
19- 26 F8.4 deg RASdeg Right ascension at equinox J2000 from SDSS
28- 35 F8.4 deg DESdeg Declination at equinox J2000 from SDSS
37- 40 I4 --- run Run number
42- 44 I3 --- rerun Rerun number
48 I1 --- camcol Camera column
55- 57 I3 --- Field Field number
61- 64 I4 --- objId The object id within a field
66- 71 A6 --- Type Type classification of the object
73- 77 F5.2 mag umag Model magnitude in u-band
79- 83 F5.2 mag gmag Model magnitude in g-band
85- 89 F5.2 mag rmag Model magnitude in r-band
91- 95 F5.2 mag imag Model magnitude in i-band
97-101 F5.2 mag zmag Model magnitude in z-band
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Note (1): This position is obtained through model detection
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Byte-by-byte Description of file: catalog5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.6 deg RAdeg Right ascension at equinox J2000 (1)
12- 21 F10.6 deg DEdeg Declination at equinox J2000 (1)
23- 26 I4 --- release the camera and filter set used (1)
31- 36 I6 --- brickid Brick ID (1)
39- 46 A8 --- brickname Name of brick (1)
49- 53 I5 --- objid Catalog object number within this brick (1)
55- 57 A3 --- Type Morphological model (1)
60- 72 A13 3.63uJy Fg Model flux in g, in nanomaggy units (1)
74- 86 A13 3.63uJy Fr Model flux in r, in nanomaggy units (1)
88-100 A13 3.63uJy Fz Model flux in z, in nanomaggy units (1)
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Note (1): All properties are available from the DESI DR9 Tractor catalog.
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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), 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).
The DESI Legacy Imaging Surveys consist of three individual and
complementary projects: the Dark Energy Camera Legacy Survey (DECaLS),
the Beijing-Arizona Sky Survey (BASS), and the Mayall z-band Legacy
Survey (MzLS). DECaLS, BASS and MzLS together include data obtained,
respectively, at the Blanco telescope, Cerro Tololo Inter-American
Observatory, NSF's NOIRLab; the Bok telescope, Steward Observatory,
University of Arizona; and the Mayall telescope, Kitt Peak National
Observatory, NOIRLab. NOIRLab is operated by the Association of
Universities for Research in Astronomy (AURA) under a cooperative
agreement with the National Science Foundation. Pipeline processing and
analyses of the data were supported by NOIRLab and the Lawrence Berkeley
National Laboratory (LBNL). Legacy Surveys also uses data products from
the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE),
a project of the Jet Propulsion Laboratory/California Institute of
Technology, funded by the National Aeronautics and Space Administration.
Legacy Surveys was supported by: the Director, Office of Science,
Office of High Energy Physics of the U.S. Department of Energy; the
National Energy Research Scientific Computing Center, a DOE Office of
Science User Facility; the U.S. National Science Foundation, Division of
Astronomical Sciences; the National Astronomical Observatories of China,
the Chinese Academy of Sciences and the Chinese National Natural Science
Foundation. LBNL is managed by the Regents of the University of
California under contract to the U.S. Department of Energy. The complete
acknowledgments can be found
at https://www.legacysurvey.org/acknowledgment/.
The Photometric Redshifts for the Legacy Surveys (PRLS) catalog used in
this paper was produced thanks to funding from the U.S. Department
of Energy Office of Science, Office of High Energy Physics via
grant DE-SC0007914.
(End) Patricia Vannier [CDS] 07-Mar-2025