J/A+A/519/A40ivo://CDS.VizieR/J/A+A/519/A40doi:10.26093/cds/vizier.35190040CDSAnnibali F.Bressan A.Rampazzo R.Zeilinger W.W.Vega O.Panuzzo P.2017-06-19T07:58:12Z2011-01-03T11:52:20ZCDS support team

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

cds-question@unistra.frgalaxiesvisible-astronomyspectroscopyWith the aim of constraining the source of excitation and the origin of the ionized gas in early-type galaxies (ETGs), we analyzed intermediate resolution optical spectra of a sample of 65 ETGs mostly located in low density environments. Optical emission lines are detected in 89% of the sample. The incidence and strength of emission do not correlate either with the E/S0 classification, or with the fast/slow rotator classification. Comparing the nuclear r<r_e_/16 line emission with the classical [OIII]/Hb vs [NII]/Ha diagnostic diagram, the galaxy activity is so classified: 72% of the galaxies with emission are LINERs, 9% are Seyferts, 12% are Composite/Transition objects, and 7% are non-classified. Seyferts have young luminosity-weighted ages (<5Gyr), and appear, on average, significantly younger than LINERs and Composites. Excluding the Seyferts from our sample, we find that the spread in the ([OIII], Ha or [NII]) emission strength increases with the galaxy central velocity dispersion sigma_c_. The [NII]/Ha ratio decreases with increasing galacto-centric distance, indicating either a decrease of the nebular metallicity, or a progressive "softening" of the ionizing spectrum. The average oxygen abundance of the ionized gas is slightly less than solar, and a comparison with the results obtained in Paper III (Cat. J/A+A/463/455) from Lick indices reveals that it is ~0.2dex lower than that of stars. Conclusions: the nuclear emission can be explained with photoionization by PAGB stars alone only in ~22% of the LINERs/Composite sample. On the other hand, we can not exclude an important role of PAGB star photoionization at larger radii. For the major fraction of the sample, the nuclear emission is consistent with excitation from a low-accretion rate AGN, fast shocks (200-500km/s) in a relatively gas-poor environment (n<100cm^-3^), or coexistence of the two. The derived nebular metallicities suggest either an external origin of the gas, or an overestimate of the oxygen yields by SN models.2010A&A...519A..40Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/519/A40CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/433/497 : Nearby early-type gal. with ionized gas. I. (Rampazzo+, 2005)J/A+A/445/79 : Nearby early-type gal. with ionized gas. II. (Annibali+, 2006)J/A+A/463/455 : Nearby early-type gal. with ionized gas. III. (Annibali+, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/519/A40https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/519/A40http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/519/A40https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/519/A40https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/519/A40http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/519/A40GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/519/A40/table1 (Sample overview)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/519/A40/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/519/A40/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/519/A40/table1?GETtext/xml+votable180.050000true7.31279172.86404720.0055555555555555566/2142 4188 4520 8193 8195-8196 13336 17032 18103 23088 24951 25383 25533 25647 26065 26091 26125 26313 27186 27367 27773 27936 28200 28221 33271 33802 33954 34521 34534 34540 35923 36153 36172 36247 36261 36632 36785 37266 38347 38693 38704 43259 43306 43602 43626 43700 43828 43830 43891 44247 44995 45469 45636 45770 45883 46017 46568 46738 46740 46811 47157 47201 47386 47409 48160https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/519/A40?format=asciiOpticaldefaultJ/A+A/519/A40/table1Sample overviewrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalaxyGalaxy namemeta.id;meta.maincharprimaryMType1RSA (Cat. VII/51) morphological typesrc.morph.typecharMType2RC3 (Cat. VII/155) morphological typesrc.morph.typecharsigmac? Central velocity dispersion (from HYPERLEDA, Cat. VII/237)km/sphys.veloc.dispersionintnullablereEffective radius from RC3 (Cat. VII/155)arcsecphys.angSizefloatHVGalaxy systemic velocitykm/sphys.veloc;src.class.starGalaxyintrho? Richness parameter rho_xyz_, in gal/Mpc^3^ (1)Mpc**-3src.class.richnessfloatnullableAge? Age (from paper II, Cat. J/A+A/445/79)Gyrtime.agefloatnullablee_Age? rms uncertainty on AgeGyrstat.error;time.agefloatnullableZ? Metallicity (from paper II, Cat. J/A+A/445/79)phys.abund.Zfloatnullablee_Z? rms uncertainty on Zstat.error;src.redshiftfloatnullable[a/Fe]? {alpha}/Fe abundance ratio (from paper II, Cat. J/A+A/445/79)phys.abundfloatnullablee_[a/Fe]? rms uncertainty on [a/Fe]stat.error;phys.abundfloatnullableData[*] * when data in tables 2 and 3meta.notecharPrevdata from papers I (J/A+A/433/497), II (J/A+A/445/79) and III (J/A+A/463/455)meta.ref.urlcharSimbadSimbad column added by the CDScharNEDSimbad column added by the CDScharLEDASimbad column added by the CDSchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/A+A/519/A40/emlinesEmission-line fluxes and equivalent fluxesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalaxyGalaxy identifiermeta.id;meta.maincharReg[1/4] Annulus code (G1)meta.codeintE(B-V)Reddeningphot.color.excessfloate_E(B-V)Error on reddeningstat.errorfloatFOII? OII 3727 flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FOII? Error on FOII 37271e-19W.m**-2.arcsec**-2stat.errorfloatnullableFNeIII? NeIII 3869 flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FNeIII? Error on FNeIII 38691e-19W.m**-2.arcsec**-2stat.errorfloatnullableFHb? Hbeta flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FHb? Error on FHbeta1e-19W.m**-2.arcsec**-2stat.errorfloatnullableFOIII59? OIII 4959 flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FOIII59? Error on FOIII 49591e-19W.m**-2.arcsec**-2stat.errorfloatnullableFOIII07? OIII 5007 flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FOIII07? Error on FOIII 50071e-19W.m**-2.arcsec**-2stat.errorfloatnullableFOI? OI 6300 flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FOI? Error on FOI 63001e-19W.m**-2.arcsec**-2stat.errorfloatnullableFNII48? NII 6548 flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FNII48? Error on FNII 65481e-19W.m**-2.arcsec**-2stat.errorfloatnullableFHa? Halpha flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FHa? Error on FHalpha1e-19W.m**-2.arcsec**-2stat.errorfloatnullableFNII84? NII 6584 flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FNII84? Error on FNII 65841e-19W.m**-2.arcsec**-2stat.errorfloatnullableFSII17? SII 6717 flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FSII17? Error on FSII 67171e-19W.m**-2.arcsec**-2stat.errorfloatnullableFSII31? SII 6731 flux (G2)1e-19W.m**-2.arcsec**-2phot.fluxfloatnullablee_FSII31? Error on FSII 67311e-19W.m**-2.arcsec**-2stat.errorfloatnullableWOII? OII 3727 equivalent width (G2)0.1nmspect.line.eqWidthfloatnullablee_WOII? Error on WOII 37270.1nmstat.errorfloatnullableWNeIII? NeIII 3869 equivalent width (G2)0.1nmspect.line.eqWidthfloatnullablee_WNeIII? Error on WNeIII 38690.1nmstat.errorfloatnullableWHb? Hbeta equivalent width (G2)0.1nmspect.line.eqWidth;em.line.Hbetafloatnullablee_WHb? Error on WHbeta0.1nmstat.errorfloatnullableWOIII59? OIII 4959 equivalent width (G2)0.1nmspect.line.eqWidth;em.line.OIIIfloatnullablee_WOIII59? Error on WOIII 49590.1nmstat.errorfloatnullableWOIII07? OIII 5007 equivalent width (G2)0.1nmspect.line.eqWidth;em.line.OIIIfloatnullablee_WOIII07? Error on WOIII 50070.1nmstat.errorfloatnullableWOI? OI 6300 equivalent width (G2)0.1nmspect.line.eqWidthfloatnullablee_WOI? Error on WOI 63000.1nmstat.errorfloatnullableWNII48? NII 6548 equivalent width (G2)0.1nmspect.line.eqWidthfloatnullablee_WNII48? Error on WNII 65480.1nmstat.errorfloatnullableWHa? Halpha equivalent width (G2)0.1nmspect.line.eqWidth;em.line.Halphafloatnullablee_WHa? Error on WHalpha0.1nmstat.errorfloatnullableWNII84? NII 6584 equivalent width (G2)0.1nmspect.line.eqWidthfloatnullablee_WNII84? Error on WNII 65840.1nmstat.errorfloatnullableWSII17? SII 6717 equivalent width (G2)0.1nmspect.line.eqWidthfloatnullablee_WSII17? Error on WSII 67170.1nmstat.errorfloatnullableWSII31? SII 6731 equivalent width (G2)0.1nmspect.line.eqWidthfloatnullablee_WSII31? Error on WSII 67310.1nmstat.errorfloatnullable