J/A+A/699/A350 HOLISMOKES. XVI. Lens search in HSC-PDR3 (Schuldt+, 2025)
HOLISMOKES. XVI: Lens search in HSC-PDR3 with a neural network committee
and post-processing for false-positive removal.
Schuldt S., Canameras R., Shu Y., Andika I.T., Bag S., Grillo C., Melo A.,
Suyu S.H., Taubenberger S.
<Astron. Astrophys. 699, A350 (2025)>
=2025A&A...699A.350S 2025A&A...699A.350S (SIMBAD/NED BibCode)
ADC_Keywords: Gravitational lensing ; Morphology ; Models
Keywords: gravitational lensing: strong - methods: data analysis
Abstract:
We have carried out a systematic search for galaxy-scale lenses
exploiting multi-band imaging data from the third public data release
of the Hyper Suprime-Cam (HSC) survey with the focus on false-positive
removal, after applying deep learning classifiers to all ∼110 million
sources with i-Kron radius above 0.8". To improve the performance, we
tested the combination of multiple networks from our previous lens
search projects and found the best performance by averaging the scores
from five of our networks. Although this ensemble network leads
already to a false-positive rate (FPR) of ∼0.01% at a true-positive
rate (TPR) of 75% on known real lenses, we have elaborated techniques
to further clean the network candidate list before visual inspection.
In detail, we tested the rejection using SExtractor and the modeling
network from HOLISMOKES IX, which resulted together in a candidate
rejection of 29% without lowering the TPR. After the initial visual
inspection stage to remove obvious non-lenses, 3408 lens candidates
of the ∼110 million parent sample remained. We carried out a
comprehensive multi-stage visual inspection involving eight
individuals and identified finally 95 grade A (average grade G≥2.5)
and 503 grade B (2.5>G≥1.5) lens candidates, including 92 discoveries
showing clear lensing features that are reported for the first time.
This inspection also incorporated a novel environmental
characterization using histograms of photometric redshifts. We
publicly release the average grades, mass model predictions, and
environment characterization of all visually inspected candidates,
while including references for previously discovered systems, which
makes this catalog one of the largest compilation of known lenses. The
results demonstrate that (1) the combination of multiple networks
enhances the selection performance and (2) both automated masking
tools as well as modeling networks, which can be easily applied to
hundreds of thousands of network candidates expected in the near
future of wide-field imaging surveys, help reduce the number of false
positives that is the main limitation in lens search to date.
Description:
Coordinates and characteristics of the high-confidence lens candidates
identified with our committee network (table2.dat) and visually
inspected.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 535 14152 Characteristics of strong lens candidates
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See also:
J/A+A/644/A163 : Pan-STARRS lens candidates from neural networks
(Canameras+ 2021)
J/A+A/653/L6 : HSC-SSP lens candidates from neural networks
(Canameras+, 2021)
J/A+A/662/A4 : Strong-lens candidates from HSC-SSP PDR2 (Shu+, 2022)
J/A+A/693/A291 : Characteristics of 162 strong lenses (Schuldt+, 2025)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Name Name for grade A and B lens candidates,
HSCJHHMM+DDMM
15- 36 F22.17 deg RAdeg Right Ascension of the inspected candidate
(J2000)
38- 61 F24.19 deg DEdeg Declination of the inspected candidate
(J2000)
63- 73 F11.8 arcsec irad Kron radius in the i band provided by HSC
used for source selection (see Sect. 2)
75- 92 F18.16 --- p Average score predicted by the
network committee
94- 98 F5.3 --- G [0/3] Average grade between 0 and 3 obtained
through visual inspection (see Sect. 4) (1)
100-118 F19.17 --- s_G Standard deviation of obtained visual
inspection grades
120 I1 --- Ngraders Number of visual inspectors (see Sect. 4)
122-126 A5 --- Binary Flag to indicate sources inspected only in
the binary stage (two different graders)
128-132 A5 --- Round1 Flag to indicate systems inspected also in
the first round (four different graders)
134-138 A5 --- Round2 Flag to indicate systems inspected also in
the second round (eight different graders)
140-144 A5 --- A24 Flag to indicate if system jointly inspected
with candidates discovered by Andika et al.
(2024, arXiv:2412.12709)
146-150 A5 --- C21 Flag to indicate systems discovered by this
network committee but not re-inspected.
Instead, we report the visual inspection
grade from our earlier work Canameras et al.
(2021A&A...653L...6C 2021A&A...653L...6C, Cat. J/A+A/653/L6)
152-156 A5 --- S22 Flag to indicate systems discovered by this
network committee but not re-inspected.
Instead, we report the visual inspection
grade from our earlier work Shu et al.
(2022A&A...662A...4S 2022A&A...662A...4S, Cat. J/A+A/662/A4)
158-162 A5 --- S25 Flag to indicate systems discovered by this
network committee but not re-inspected.
Instead, we report the visual inspection
grade from our earlier work S25
164-185 E22.19 arcsec xmed ?=- x center coordinate predicted by the
modeling network (2)
187-206 F20.18 arcsec e_xmed ?=- 1 σ value for the x center
coordinate predicted by the modeling
network (2)
208-229 E22.19 arcsec ymed ?=- y center coordinate predicted by the
modeling network (2)
231-250 F20.18 arcsec e_ymed ?=- 1 σ value for the y center
coordinate predicted by the modeling
network (2)
252-273 E22.19 --- exmed ?=- x component of the complex ellipticity
predicted by the modeling network (2)
275-294 F20.18 --- e_exmed ?=- 1 σ value for the x component of
the complex ellipticity predicted by the
modeling network (2)
296-317 E22.19 --- eymed ?=- y component of the complex ellipticity
predicted by the modeling network (2)
319-338 F20.18 --- e_eymed ?=- 1 σ value for the y component of
the complex ellipticity predicted by the
modeling network (2)
340-357 F18.16 arcsec rEmed ?=- Einstein radius value of the given
candidate predicted by the modeling
network (2)
359-378 F20.18 arcsec e_rEmed ?=- 1 σ value of the Einstein radius
predicted by the modeling network (2)
380-401 E22.19 --- gam1med ?=- γ1 component of the external shear
predicted by the modeling network (2)
403-422 F20.18 --- e_gam1med ?=- 1 σ value of the γ1-component
predicted by the modeling network (2)
424-445 E22.19 --- gam2med ?=- γ2 component of the external shear
predicted by the modeling network (2)
447-466 F20.18 --- e_gam2med ?=- 1 σ value of the γ2-component
predicted by the modeling network (2)
468-472 A5 --- Flag Flag if the model predict is reliable, only
for systems inspected in the second round
474-478 A5 --- ODvis Flag if the system falls into a significant
overdense region
480-484 A5 --- ODz Flag if the system is in a significant
overdense environment according to the
criteria defined by Schuldt et al.
(2025A&A...693A.291S 2025A&A...693A.291S, Cat. J/A+A/693/A291)
486-505 F20.18 --- z ? Photometric redshift value (3)
507-510 I4 --- Nmax ? Peak of the photo-z histogram following the
procedure of Schuldt et al.
(2025A&A...693A.291S 2025A&A...693A.291S, Cat. J/A+A/693/A291)
512-515 F4.2 --- zlow ? Lower bound of Nmax in the photo-z
histogram indicating the redshift of the
overdensity
517-523 F7.1 --- Ntot ? Sum of objects with photo-z within a box of
200" on a side
525-535 A11 --- Ref References (4)
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Note (1): Grade as follows:
0 = no lens,
1 = to possible lens
2 = to probable lens
3 = to definite lens
Note (2): from Schuldt et al. (2023A&A...671A.147S 2023A&A...671A.147S)
Note (3): from the catalog compiled by Schuldt et al. (2025A&A...693A.291S 2025A&A...693A.291S,
Cat. J/A+A/693/A291) based on DEmP (Hsieh & Yee, 2014ApJ...792..102H 2014ApJ...792..102H),
Mizuki (Tanaka et al., 2018PASJ...70S...9T 2018PASJ...70S...9T), and
NetZ (Schuldt et al. 2021A&A...651A..55S 2021A&A...651A..55S, Cat. J/A+A/651/A55)
Note (4): List of publications that report the inspected candidate (within 5")
as lens candidate according to the HOLISMOKES Suyu et al.
(2020A&A...644A.162S 2020A&A...644A.162S) lens compilation with status of the publication, using
the following codes:
B04 = Bolton et al. (2004AJ....127.1860B 2004AJ....127.1860B)
C07 = Cabanac et al. (2007A&A...461..813C 2007A&A...461..813C)
B08 = Bolton et al. (2008ApJ...684..248B 2008ApJ...684..248B)
G14 = Gavazzi et al. (2014ApJ...785..144G 2014ApJ...785..144G, Cat. J/ApJ/785/144)
H15 = Holwerda et al. (2015MNRAS.449.4277H 2015MNRAS.449.4277H, Cat. J/MNRAS/449/4277)
M16 = More et al. (2016MNRAS.455.1191M 2016MNRAS.455.1191M)
P16 = Paraficz et al. (2016A&A...592A..75P 2016A&A...592A..75P, Cat. J/A+A/592/A75)
S16 = Shu et al. (2016ApJ...824...86S 2016ApJ...824...86S, Cat. J/ApJ/824/86)
D17 = Diehl et al. (2017ApJS..232...15D 2017ApJS..232...15D, Cat. J/ApJS/232/15)
J17 = Jacobs et al. (2017MNRAS.471..167J 2017MNRAS.471..167J)
S18 = Sonnenfeld et al. (2018PASJ...70S..29S 2018PASJ...70S..29S)
W18 = Wong et al. (2018ApJ...867..107W 2018ApJ...867..107W, Cat. J/ApJ/867/107)
J19 = Jacobs et al. (2019ApJS..243...17J 2019ApJS..243...17J, Cat. J/ApJS/243/17)
L19 = Li et al. (2019MNRAS.482..313L 2019MNRAS.482..313L)
P19 = Petrillo et al. (2019MNRAS.484.3879P 2019MNRAS.484.3879P, Cat. J/MNRAS/484/3879)
H20 = Huang et al. (2020ApJ...894...78H 2020ApJ...894...78H, Cat. J/ApJ/894/78H)
C20 = Chan et al. (2020A&A...636A..87C 2020A&A...636A..87C, Cat. J/A+A/636/A87C)
Ca20 = Canameras et al. (2020A&A...644A.163C 2020A&A...644A.163C, Cat. J/A+A/644/A163)
Cao20 = Cao et al. (2020MNRAS.499.3610C 2020MNRAS.499.3610C, Cat. J/MNRAS/499/3610)
L20 = Li et al. (2020ApJ...899...30L 2020ApJ...899...30L)
J20 = Jaelani et al. (2020MNRAS.494.3156J 2020MNRAS.494.3156J)
S20 = Sonnenfeld et al. (2020A&A...642A.148S 2020A&A...642A.148S, J/A+A/642/A148)
C21 = Canameras et al. (2021A&A...653L...6C 2021A&A...653L...6C, Cat. J/A+A/653/L6)
H21 = Huang et al. (2021ApJ...909...27H 2021ApJ...909...27H, Cat. J/ApJ/909/27)
L21 = Li et al. (2021ApJ...923...16L 2021ApJ...923...16L)
T21 = Talbot et al. (2021MNRAS.502.4617T 2021MNRAS.502.4617T)
R22 = Rojas et al. (2022A&A...666A...1S 2022A&A...666A...1S, Cat. J/A+A/666/A1)
S22 = Shu et al. (2022A&A...662A...4S 2022A&A...662A...4S, Cat. J/A+A/662/A4)
Sa22 = Savary et al. (2022A&A...666A...1S 2022A&A...666A...1S, Cat. J/A+A/666/A1)
St22 = Stein et al. (2022ApJ...932..107S 2022ApJ...932..107S)
W22 = Wong et al. (2022PASJ...74.1209W 2022PASJ...74.1209W, Cat. J/PASJ/74/1209)
Z22 = Zhong et al. (2022RAA....22f5014Z 2022RAA....22f5014Z, Cat. J/other/RAA/22.F5014)
A23 = Andika et al. (2023A&A...678A.103A 2023A&A...678A.103A, Cat. J/A+A/678/A103)
J24 = Jaelani et al. (2024MNRAS.535.1625J 2024MNRAS.535.1625J)
G24 = Grespan et al. (2024A&A...688A..34G 2024A&A...688A..34G)
St24 = Storfer et al. (2024ApJS..274...16S 2024ApJS..274...16S)
S25 = Schuldt et al. (2025A&A...693A.291S 2025A&A...693A.291S, Cat. J/A+A/693/A291)
ML = the master lens catalog at http://admin.masterlens.org,
Guoyou Sun = corresponds to candidates identified by an amateur astronomer,
Guoyou Sun, through visual inspections of HSC cutouts
(see http://sunguoyou.lamost.org/glc.html.).
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Acknowledgements:
Stefan Schuldt, stefan.schuldt(at)unimi.it
References:
Suyu et al., Paper I 2020A&A...644A.162S 2020A&A...644A.162S
Canameras et al. Paper II 2020A&A...644A.163C 2020A&A...644A.163C, Cat. J/A+A/644/A163
Huber et al. Paper III 2021A&A...646A.110H 2021A&A...646A.110H
Schuldt et al. Paper IV 2021A&A...646A.126S 2021A&A...646A.126S
Bayer et al. Paper V 2021A&A...653A..29B 2021A&A...653A..29B
Canameras et al. Paper VI 2021A&A...653L...6C 2021A&A...653L...6C, Cat. J/A+A/653/L6
Huber et al. Paper VII 2022A&A...658A.157H 2022A&A...658A.157H
Shu et al., Paper VIII 2022A&A...662A...4S 2022A&A...662A...4S, Cat. J/A+A/662/A4
Schuldt et al. Paper IX 2023A&A...671A.147S 2023A&A...671A.147S
Schuldt et al. Paper X 2023A&A...673A..33S 2023A&A...673A..33S
Canameras et al. Paper XI 2024A&A...692A..72C 2024A&A...692A..72C
Huber et al. Paper XII 2024A&A...692A.132H 2024A&A...692A.132H
Schuldt et al. Paper XIII 2025A&A...693A.291S 2025A&A...693A.291S, Cat. J/A+A/693/A291
Grupa et al. Paper XIV 2025A&A...693A.292G 2025A&A...693A.292G
Melo et al., Paper XV 2025A&A...698A.264M 2025A&A...698A.264M
(End) Stefan Schuldt [UniMi, Italy], Patricia Vannier [CDS] 23-Jun-2025