J/ApJS/174/337ivo://CDS.VizieR/J/ApJS/174/337doi:10.26093/cds/vizier.21740337CDSMazzuca L.M.Knapen J.H.Veilleux S.Regan M.W.2017-12-15T10:54:59Z2009-11-06T15:48:16ZCDS support team

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

cds-question@unistra.frring-galaxiesline-intensitiesh-ii-regionsvisible-astronomyh-alpha-photometryWe present results from a photometric H{alpha} survey of 22 nuclear rings, aiming to provide insight into their star formation properties, including age distribution, dynamical timescales, star formation rates, and galactic bar influence. We find a clear relationship between the position angles and ellipticities of the rings and those of their host galaxies, which indicates the rings are in the same plane as the disk and circular. We use population synthesis models to estimate ages of each H{alpha}-emitting (HII) region, which range from 1 to 10Myr throughout the rings. We find that approximately half of the rings contain azimuthal age gradients that encompass at least 25% of the ring, although there is no apparent relationship between the presence or absence of age gradients and the morphology of the rings or their host galaxies. NGC 1343, NGC 1530, and NGC 4321 show clear bipolar age gradients, where the youngest HII regions are located near the two contact points of the bar and ring. We speculate in these cases that the gradients are related to an increased mass inflow rate and/or an overall higher gas density in the ring, which would allow for massive star formation to occur on short timescales, after which the galactic rotation would transport the HII regions around the ring as they age. Two-thirds of the barred galaxies show correlation between the locations of the youngest HII region(s) in the ring and the location of the contact points, which is consistent with predictions from numerical modeling.2008ApJS..174..337Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/174/337CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/128/2170 : H{alpha} imaging of irregular galaxies (Hunter+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/174/337https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/174/337http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/174/337https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/174/337https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/174/337http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/174/337GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/174/337/galaxies (Galaxy list)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/174/337/galaxies?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/174/337/galaxies?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/174/337/galaxies?GETtext/xml+votable180.050000true334.121667-21.4311110.0055555555555555566/2687 3862 3910 8492 9883 11372 11639 13489 15955 18415 18800 19614 19981 26303 26472 27763 35691 36261 44660 48464https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/174/337?format=asciiOpticaldefaultJ/ApJS/174/337/galaxiesGalaxy listrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGC/ICGalaxy namemeta.id;meta.maincharprimaryRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination sign (J2000)pos.eq.dec;meta.mainNHIINumber of HII regions in the galaxymeta.id;obs.fieldintSimbadSimbad column added by the CDScharNEDSimbad column added by the CDScharRemarksNotes on the HII reguions detected.meta.notecharJ/ApJS/174/337/tablesNGC or IC HII regions detected associated with the ring (tables 4 to 23 of the paper)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGC/ICGalaxy namemeta.id.parentchar[MKV2008]HII region number (1)meta.id;obs.fieldintFluxIntegrated flux (in 10^-13^erg/cm^2^/s)1e-16W.m**-2phot.flux;em.line.HalphafloatLumLuminosity (in 10^37^erg/s)1e+32Wphys.luminosityfloatEWH{alpha} equivalent width ({AA})0.1nmspect.line.eqWidth;em.line.HalphaintCorFlux[0/1] Flux correction (2)meta.codeint