J/ApJ/786/L10ivo://CDS.VizieR/J/ApJ/786/L10doi:10.26093/cds/vizier.17869010CDSShetty S.Cappellari M.2017-09-04T07:59:59Z2017-07-03T15:03:57ZCDS support team

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

cds-question@unistra.frgalaxiesphotometryastronomical-modelsredshiftedgalaxy-kinematicsThe stellar initial mass function (IMF) is a key parameter for studying galaxy evolution. Here we measure the IMF mass normalization for a sample of 68 field galaxies in the redshift range 0.7-0.9 within the Extended Groth Strip. To do this we derive the total (stellar + dark matter) mass-to-light [(M/L)] ratio using axisymmetric dynamical models. Within the region where we have kinematics (about one half-light radius), the models assume (1) that mass follows light, implying negligible differences between the slope of the stellar and total density profiles, (2) constant velocity anisotropy ({beta}_z_=1-{sigma}_z_^2^/{sigma}_R_^2^=0.2), and (3) that galaxies are seen at the average inclination for random orientations (i.e., i=60{deg}, where i=90{deg} represents edge-on). The dynamical models are based on anisotropic Jeans equations, constrained by Hubble Space Telescope/Advanced Camera for Surveys imaging and the central velocity dispersion of the galaxies, extracted from good-quality spectra taken by the DEEP2 survey. The population (M/L) are derived from full-spectrum fitting of the same spectra with a grid of simple stellar population models. Recent dynamical modeling results from the ATLAS^3D^ project and numerical simulations of galaxy evolution indicate that the dark matter fraction within the central regions of our galaxies should be small. This suggests that our derived total (M/L) should closely approximate the stellar M/L. Our comparison of the dynamical (M/L) and the population (M/L) then implies that for galaxies with stellar mass M_*_>~10^11^ M_{sun}_, the average normalization of the IMF is consistent with a Salpeter slope, with a substantial scatter. This is similar to what is found within a similar mass range for nearby galaxies.2014ApJ...786L..10Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/786/L10CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/301 : The DEEP2-DR1 Photometric Catalog (Coil+ 2004)J/ApJ/625/6 : Galaxy groups in the DEEP2 Galaxy Redshift Survey (Gerke+, 2005)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/786/L10https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/786/L10http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/786/L10https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/786/L10https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/786/L10http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/786/L10GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/786/L10/table1 (Results of dynamical models and multiple population fitting)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/786/L10/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/786/L10/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/786/L10/table1?GETtext/xml+votable180.050000true214.381956752.39762220.0055555555555555566/11424 11425https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/786/L10?format=asciiOpticaldefaultJ/ApJ/786/L10/table1Results of dynamical models and multiple population fittingrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDDEEP2 identifier (DEEP2-GRS NNNNNNNN in Simbad)meta.id;meta.mainintzDEEP2 estimated redshiftsrc.redshiftfloatBMagAbsolute B-band Vega magnitude (1)magphot.mag;em.opt.BfloatReffEffective radius (2)arcsecphys.angSizefloatsigmaAperture velocity dispersionkm/sphys.veloc.dispersion;instr.fovinte_sigmaError in sigmakm/sstat.errorint(M/L)JAMJeans Anisotropic multi-Gaussian expansion (JAM) dynamical mass-to-light ratio (3)solMass/solLumpos.parallax.dynfloat(M/L)SalSalpeter population mass-to-light ratio (4)solMass/solLumphys.composition.massLightRatiofloatSimbadSimbad column added by the CDSmeta.ref.urlchar_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.main