J/A+A/698/A276ivo://CDS.VizieR/J/A+A/698/A276doi:10.26093/cds/vizier/bc-nt/lchgCDSJohn William A.Jalan P.Bilicki M.Hellwing W.A.Thuruthipilly H.,Nakoneczny S.J.2026-08-03T06:54:59Z2025-06-20T12:14:39ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgalaxiescatalogsredshiftedvisible-astronomyWe employ deep learning (DL) to improve photometric redshifts (photo-zs) in the Kilo-Degree Survey Data Release 4 Bright galaxy sample (KiDS-Bright DR4). This dataset, used as foreground for KiDS lensing and clustering studies, is flux-limited to r<20mag with mean z=0.23 and covers 1000deg^2^. Its photo-zs were previously derived with artificial neural networks from the ANNz2 package trained on the Galaxy And Mass Assembly (GAMA) spectroscopy. Here we considerably improve over these previous redshift estimations by building a DL model, Hybrid-z, which combines an Inception-based convolutional neural network operating on four-band KiDS images with an artificial neural network using nine-band magnitudes from KiDS+VIKING. The Hybrid-z framework provides state-of-the-art photo-zs for KiDS-Bright, with negligible mean residuals of O(10^-4^) and scatter at the level of 0.014(1+z) - representing a reduction by 20% over the previous nine-band derivations with ANNz2. Our photo-zs are robust and stable independently of galaxy magnitude, redshift, and color. We check our photo-z model performance on test data drawn from GAMA, as well as from other KiDS-overlapping wide-angle spectroscopic surveys, namely SDSS, 2dFLenS and 2dFGRS. We find stable behavior and consistent improvement over ANNz2 throughout. We finally apply Hybrid-z trained on GAMA to the entire KiDS-Bright DR4 sample of 1.2 million galaxies.2025A&A...698A.276Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/698/A276CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/383 : The ESO KiDS-DR5 multi-band source catalog (Wright+ 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/698/A276https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/698/A276http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/698/A276https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/698/A276https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/698/A276http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/698/A276GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/698/A276/catalog (Photometric redshift estimates for over 1.2 million galaxies in the KiDS-Bright sample (r<20mag))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/698/A276/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/698/A276/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/698/A276/catalog?GETtext/xml+votable180.050000true359.45932806-28.4584450.0055555555555555564/1027-1029 1032-1034 1365 1621-1622 1625-1626 1637 1642 1685-1686 1689-1690 1706 1961-1962 2207 2223 2227 2229 2232-2234 2243-2244 2246 2249-2250 2911 2931-2934 2936-2937 5/1024-1026 2048 2050 4103 4107 4120-4122 4124 4140 4144 4160 4224 5459 5468-5469 6397-6399 6461-6463 6477-6479 6481-6483 6492-6494 6497-6499 6508-6510 6512-6514 6553-6558 6561-6563 6565-6567 6572-6574 6576-6578 6592-6594 6717 6719 6733-6735 6737-6739 6748-6750 6754-6755 6764 6766 6768-6770 6819 6828 6830 6848-6849 6912-6914 7823 7843 7852 7856 8823 8827 8887 8891 8903 8907 8913 8921-8922 8940 8944 8967 8971 8982-8983 8988-8990 8993-8995 9004 9008-9009 9088 10239 11262-11263 11639 11643 11719 11723 11740 11753 11756 11758 11760 6/4108 4112 4128 8196-8198 8204 8224 16406-16407 16409-16411 16421-16423 16425-16427 16492-16494 16500-16502 16504-16505 16564-16566 16568-16570 16580 16582 16584-16585 16644-16646 16648-16650 16900-16902 16904-16906 21829-21831 21833 21835 21860-21861 21863 21880-21881 21884 25567 25583 25587 25823 25839 25843 25887 25903 25907 25921 25923 25980 26060 26064 26080 26159 26173-26175 26189-26191 26209-26211 26236 26243 26257-26259 26300 26316 26320 26336 26380 26384 26400 26847 26867 26873 26911 26931 26947 27004 27013-27015 27060-27062 27084 27088 27104 27221 27270-27271 27273-27275 27288 27290-27291 27316 27318-27319 27324 27401 27404 27408 27660 27664 27680 31286 31289-31291 31338 31365-31367 31369-31371 31412-31414 31416-31418 31428 31430 31432-31434 34534 34537-34540 34542-34543 34554 35287 35291 35303 35307 35543 35547 35559 35563 35611 35623 35627 35648-35649 35651 35661 35663 35680 35682-35683 35692-35694 35696-35698 35700-35701 35764-35766 35768-35770 35782 35784-35786 35861-35863 35865-35867 35877-35879 35883 35922-35923 35926 35964 35969-35971 36020-36022 36024 36026 36040-36041 36044 36048 36128 36356-36358 36360-36362 40949-40951 40953-40955 45035-45036 45038-45039 45043 45045-45047 46549-46551 46553-46555 46565-46567 46569-46571 46805-46807 46813 46869-46871 46873-46875 46885-46887 46889-46891 46964-46966 46968-46970 47009 47021 47028-47030 47036 47044-47046 47048-47050 47052 47072https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/698/A276?format=asciiOpticaldefaultJ/A+A/698/A276/catalogPhotometric redshift estimates for over 1.2 million galaxies in the KiDS-Bright sample (r<20mag)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDSource identifier from KiDS DR4 catalog (ESO ID), KiDSDR4 JHHMMSS.sss+DDMMSS.ssmeta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination (J2000)degpos.eq.dec;meta.mainindexedrmagZero-point calibrated and extinction-corrected Kron-like elliptical aperture magnitude in the r bandmagphot.mag;em.opt.Rdoublee_rmagRMS error for MAG_AUTOmagstat.error;phot.magdoubleMaskKiDS 9-band bitmask valuemeta.codeintmasked[0/1] Quality flag: 0 = clean, 1 = maskedmeta.code.qualintzphHybridzPhotometric redshift from Hybrid-z modelsrc.redshift.photdouble