J/A+A/702/A57ivo://CDS.VizieR/J/A+A/702/A57doi:10.26093/cds/vizier/bc-ny/lfhCDSHviding R.E.de Graaff A.Miller T.B.Setton D.J.Greene J.E.,Labbe I.Brammer G.Bezanson R.Boogaard L.A.Cleri N.J.Leja J.,Maseda M.V.McConachie I.Matthee J.Naidu R.P.Oesch P.A.Wang B.,Whitaker K.E.Williams C.C.2026-08-31T14:25:37Z2025-10-07T11:16:32ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiredshiftedinfrared-photometryspectroscopyThe physical nature of Little Red Dots (LRDs), a population of compact, red galaxies revealed by JWST, remains unclear. Photometric samples are constructed from varying selection criteria with limited spectroscopic follow-up available to test intrinsic spectral shapes and prevalence of broad emission lines. We use the RUBIES survey, a large spectroscopic program with wide color-morphology coverage and homogeneous data quality, to systematically analyze the emission-line kinematics, spectral shapes, and morphologies of ~1500 galaxies at z>3.1. We identify broad Balmer lines via a novel fitting approach that simultaneously models NIRSpec/PRISM and G395M spectra, yielding 80 broad-line sources with 28 (35%) at z>6. A large subpopulation naturally emerges from the broad Balmer line sources, with 36 exhibiting 'v-shaped' UV-to-optical continua and a dominant point source component in the rest-optical; we define these as spectroscopic LRDs, constituting the largest such sample to date. Strikingly, the spectroscopic LRD population is largely recovered when either a broad line or rest-optical point source is required in combination with a v-shaped continuum, suggesting an inherent link between these three defining characteristics. We compare the spectroscopic LRD sample to published photometric searches. Although these selections have high accuracy, 80%-95% down to F444W<26.5, only 50%-80% of the RUBIES LRDs were photometrically identified, depending on the selection criteria used. The remainder were missed due to a mixture of faint rest-UV photometry, comparatively blue rest-optical colors, or highly uncertain photometric redshifts. Our findings highlight that well-selected spectroscopic campaigns are essential for robust LRD identification, while photometric criteria require refinement to capture the full population.2025A&A...702A..57Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/702/A57CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/702/A57https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/702/A57http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/702/A57https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/702/A57https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/702/A57http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/702/A57GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/702/A57/tableb1 (RUBIES zspec>3.1 broad Balmer line galaxies)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/702/A57/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/702/A57/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/702/A57/tableb1?GETtext/xml+votable180.050000true34.2441997408704-5.24587137333110.0055555555555555566/11425 17679 17690https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/702/A57?format=asciiInfrareddefaultJ/A+A/702/A57/tableb1RUBIES zspec>3.1 broad Balmer line galaxiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintField[UDS EGS] Field nameobs.fieldcharIDSource IDmeta.id;meta.mainintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainzspSpectroscopic redshift (1)src.redshiftfloatSimbadSimbad column added by the CDSmeta.ref.urlchardWAIC{DELTA}WAIC, Widely Applicable Information Criterionmeta.code.qualdoubleFWHMBroad balmer line FWHM (2)km/sspect.line.width;spect.linedoublee_FWHMBroad balmer line FWHM errorkm/sstat.error;phys.angSizedoubleF444WF444W magnitude (3)magphot.mag;em.IR.4-8umdouble