J/MNRAS/495/2720ivo://CDS.VizieR/J/MNRAS/495/2720doi:10.26093/cds/vizier.74952720CDSAngthopo J.Ferreras I.Silk J.2024-08-21T20:14:41Z2023-09-05T15:21:37ZCDS support team

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

cds-question@unistra.frgalaxiesgalaxy-kinematicsvisible-astronomyspectroscopyThe green valley (GV) represents an important transitional state from actively star-forming galaxies to passively evolving systems. Its traditional definition, based on colour, rests on a number of assumptions that can be subjected to non-trivial systematics. In Angthopo, Ferreras & Silk (2019MNRAS.488L..99A), we proposed a new definition of the GV based on the 4000{AA} break strength. In this paper, we explore in detail the properties of the underlying stellar populations by use of ~230 thousand high-quality spectra from the Sloan Digital Sky Survey (SDSS), contrasting our results with a traditional approach via dust-corrected colours. We explore high-quality stacked SDSS spectra, and find a population trend that suggests a substantial difference between low- and high-mass galaxies, with the former featuring younger populations with star formation quenching, and the latter showing older (post-quenching) populations that include rejuvenation events. Subtle but measurable differences are found between a colour-based approach and our definition, especially as our selection of GV galaxies produces a cleaner 'stratification' of the GV, with more homogeneous population properties within sections of the GV. Our definition based on 4000{AA} break strength gives a clean representation of the transition to quiescence, easily measurable in the upcoming and future spectroscopic surveys.2020MNRAS.495.2720Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/495/2720CatalogResearchIsServedByTAP VizieR generic servicerelated-toV/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/495/2720https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/495/2720http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/495/2720https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/495/2720https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/495/2720http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/495/2720GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/MNRAS/495/2720/tablea1Number of SDSS galaxy spectra in the upper and lower sections of the green valley, following the definition of GV based on the 4000{AA} break strengthrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCritSelection criteria (1)meta.notecharvdispVelocity dispersion intervalkm/sphys.veloc.dispersioncharNLGVNumber of galaxy spectra in the lower section of green valleymeta.numberintfSFLGVFraction of galaxies in the LGV classified as star-forming (2)%meta.numberfloate_fSFLGVError on fSFLGV%stat.errorfloatfQLGVFraction of galaxies in the LGV classified as quiescent (2)%meta.numberfloate_fQLGVError on fQLGV%stat.errorfloatfAGNLGVFraction of galaxies in the LGV classified as AGN (2)%meta.numberfloate_fAGNLGVError on fAGNLGV%stat.errorfloatNUGVNumber of galaxy spectra in the upper section of green valleymeta.numberintfSFUGVFraction of galaxies in the UGV classified as star-forming (2)%meta.numberfloate_fSFUGVError on fSFUGV%stat.errorfloatfQUGVFraction of galaxies in the UGV classified as quiescent (2)%meta.numberfloate_fQUGVError on fQUGV%stat.errorfloatfAGNUGVFraction of galaxies in the UGV classified as AGN (2)%meta.numberfloate_fAGNUGVError on fAGNUGV%stat.errorfloatJ/MNRAS/495/2720/tabled1Probabilities of BC, GV, or RS membership assigned to each galaxy from the SDSS setrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPlateSDSS plate spectral identifiermeta.id;meta.mainintMJDSDSS Modified Julian Date spectral identifierdtime.epochintindexedFiberSDSS Fiber spectral identifiermeta.idintDn4000Break strength at 4000{AA} (1)spect.indexfloatvdispVelocity dispersion (1)km/sphys.veloc.dispersionfloatPBCProbability of belonging to the Blue Cloudstat.probabilityfloatPGVProbability of belonging to the Green Valleystat.probabilityfloatPRSProbability of belonging to the Red Sequencestat.probabilityfloatSpInteractive spectrum from SDSS-DR14meta.ref.urlchar