J/A+A/706/A261ivo://CDS.VizieR/J/A+A/706/A261CDSGimenez-Alcazar A.Amorin R.Vilchez J.M.Hernan-Caballero A.,Gonzalez-Otero M.Arroyo-Polonio A.Iglesias-Paramo J.,Lumbreras-Calle A.Fernandez-Ontiveros J.A.Bonatto L.,Gonzalez Delgado R.M.Kehrig C.Torralba A.Rahna P.T.Jimenez-Teja Y.,Marquez I.Breda I.Alvarez-Candal A.Abramo R.Alcaniz J.Benitez N.,Bonoli S.Carneiro S.Cenarro J.Cristobal-Hornillos D.Dupke R.,Ederoclite A.Hernandez-Monteagudo C.Marin-Franch A.,Mendes de Oliveira C.Moles M.Sodre L.JrTaylor K.Varela J.,Vazquez Ramio.H.2026-03-02T06:25:50Z2026-02-13T09:27:07ZCDS support team

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

cds-question@unistra.frgalaxiesphotometryemission-line-starsredshiftedspectroscopyline-intensitiesvisible-astronomyExtreme emission line galaxies (EELGs) are expected to have an important contribution to the star formation activity and mass assembly in galaxies. Specifically. EELGs are also promising candidates to have a leading role in the cosmic reionization as their interstellar medium may allow a significant fraction of their ionizing photons to escape (>5%). Finding low-redshift analogues of these high-z galaxies is therefore essential to characterize the physical conditions in the ISM of these galaxies and understand the processes that reionized the Universe. We aim to develop a robust and efficient method for the photometric identification of EELGs using the J-PAS survey. J-PAS will cover approximately 8500deg^2^ of the sky with 54 narrow-band filters in the optical range plus i-SDSS, enabling detailed studies of the physical properties of these galaxies. In this work, we focus on an initial subset of the survey: a 30 square degree area with complete observations in all bands. We combine equivalent width (EW) measurements from J-PAS narrow-band photometry with artificial intelligence tech- niques to identify galaxies with emission lines exceeding 300{AA} in any emission line. We validate our selection using spectroscopic data from DESI/DR1 and characterize the selected sample through spectral energy distribution (SED) fitting with CIGALE. We identify 917 EELGs up to z=0.8 over 30deg^2^, achieving a purity of 95% and a completeness of 96% for i-SDSS<22.5mag. Importantly, AGN contamination has been carefully considered and is estimated to be around 5%. Furthermore, a cross-match with DESI yields 79 counterparts, whose redshifts are in excellent agreement with our photometric estimates, thereby confirming the reliability of our redshift determination. In addition, the derived emission line fluxes are in good agreement with spectroscopic measurements, reinforcing the robustness of our methodology. Moreover, the selected sample reveals strong correlations between ionizing photon production efficiency (ksi_ion_) and EW(H{beta}), which are consistent with previous observational studies at low and high redshift and theoretical expectations. Finally, most of the sources surpass the ionizing efficiency threshold required for reionization, highlighting their relevance as local analogues of early-universe galaxies.2026A&A...706A.261Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/706/A261CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/706/A261https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/706/A261http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/706/A261https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/706/A261https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/706/A261http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/706/A261GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/706/A261/table1 (Derived SED Parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/706/A261/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/706/A261/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/706/A261/table1?GETtext/xml+votable180.050000true338.518727527000822.71056581658440.0055555555555555565/1624 1626 2453 2455 2496 2856 3329 3334-3335 3341 6/6453 6455 6461 6473-6475 6500 6502 6508 9471 9640 9642-9643 9992-9994 10741 10743 11401-11403 11406 13325 13328 13330-13331 13361 13386 13408https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/706/A261?format=asciiOpticaldefaultJ/A+A/706/A261/table1Derived SED ParametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTileIDJ-PAS tile identifiermeta.id.part;meta.mainintNumberSource number within the tilemeta.id.part;meta.mainintRAJ2000Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainzSpectroscopic or photometric redshiftsrc.redshiftdoubleReffEffective radius enclosing specified fraction of fluxarcsecphys.angSizedoublelogMstarStellar mass from SED fitting (1)log(solMass)phys.massdoublee_logMstar1-sigma uncertainty from Bayesian analysis on logMstar (1)log(solMass)stat.errordoublelogSFR10Star formation rate averaged over last 10Myr (1)log(solMass.yr**-1)phys.SFRdoublee_logSFR101-sigma uncertainty from Bayesian analysis on logSFR10 (1)log(solMass.yr**-1)stat.errordoubleE(B-V)Dust attenuationmagphot.color.excessdoublee_E(B-V)1-sigma uncertainty from Bayesian analysis on E(B-V)magstat.errordoubleJ/A+A/706/A261/table2Emission line quantitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTileIDJ-PAS tile identifiermeta.id.part;meta.mainintNumberSource number within the tilemeta.id.part;meta.mainintzSpectroscopic or photometric redshiftsrc.redshiftdoublexiHalpha? Ionizing photon production efficiency from H-alpha (in Hz/erg unit) (1)1e+07Hz.J**-1phys.ionizParam.raddoublenullablee_xiHalpha? 1-sigma uncertainty on xi_Halpha1e+07Hz.J**-1stat.errordoublenullablexiHbeta? Ionizing photon production efficiency from H-beta (in Hz/erg unit) (1)1e+07Hz.J**-1phys.ionizParam.raddoublenullablee_xiHbeta? 1-sigma uncertainty on xi_Hbeta1e+07Hz.J**-1stat.errordoublenullableFHalpha? H-alpha line flux (in 10^-19^erg/s/cm^2/{AA} unit)1e-20W.m**-2.nm**-1meta.unit;phot.flux;spect.linedoublenullablee_FHalpha? 1-sigma uncertainty on FHalpha (in 10^-19^erg/s/cm^2/{AA} unit)1e-20W.m**-2.nm**-1stat.errordoublenullableFHbeta? H-beta line flux (in 10^-19^erg/s/cm^2/{AA} unit)1e-20W.m**-2.nm**-1meta.unit;phot.flux;spect.linedoublenullablee_FHbeta? 1-sigma uncertainty on FHbetaa (in 10^-19^erg/s/cm^2/{AA} unit)1e-20W.m**-2.nm**-1stat.errordoublenullableEWHalpha? H-alpha equivalent width (in {AA} unit)0.1nmspect.line.eqWidthdoublenullablee_EWHalpha? 1-sigma uncertainty on EWHalpha (in {AA} unit)0.1nmstat.errordoublenullableEWHbeta? H-beta equivalent width (in {AA} unit)0.1nmspect.line.eqWidthdoublenullablee_EWHbeta? 1-sigma uncertainty on EWHbeta (in {AA} unit)0.1nmstat.errordoublenullableEWOIII5007? Line [O III] 5007 A equivalent width (in {AA} unit)0.1nmspect.line.eqWidthdoublenullablee_EWOIII5007? 1-sigma uncertainty on EWOIII5007 (in {AA} unit)0.1nmstat.errordoublenullable