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The SAURON Survey Spheroids,Spheroids, Bulges,Bulges, andand HSTHST Tim de Zeeuw Leiden Observatory z EarlyEarly-- andand latelate--typetype galaxiesgalaxies z E/S0E/S0 galaxiesgalaxies z BulgesBulges ofof spiralspiral galaxiesgalaxies z EmissionEmission--lineline gasgas z CentralCentral blackblack holesholes z TheThe FutureFuture Early-type Late-type SpiralSpiral GalaxiesGalaxies EllipticalElliptical GalaxiesGalaxies ‘‘ActivityActivity’’ z SomeSome galaxiesgalaxies containcontain ‘‘activeactive nucleusnucleus’’ – Radio jets, X-rays, optical spike C z Cause:Cause: supermassivesupermassive blackblack holehole FO z MostMost galaxiesgalaxies activeactive inin thethe pastpast z BlackBlack holehole mustmust stillstill bebe therethere OPTICAL ⇒⇒ mostmost normalnormal galaxiesgalaxies havehave M87 (inactive)(inactive) centralcentral blackblack holehole z BlackBlack holehole influencesinfluences galaxygalaxy structurestructure && evolutionevolution RADIO GalaxyGalaxy FormationFormation andand EvolutionEvolution z GalaxiesGalaxies formform byby hierarchicalhierarchical accretion/mergingaccretion/merging – Matter clumps through gravitation – Primordial gas starts forming first stars – Stars produce heavier elements – Subsequent generations of stars contain more metals z GalaxyGalaxy encountersencounters stillstill occuroccur – Deformation, stripping, merging z BlackBlack holehole alsoalso influencesinfluences evolutionevolution ObservationalObservational ApproachesApproaches z StudyStudy veryvery distantdistant galaxiesgalaxies – Observe evolution (far away = long ago) – Objects faint and small: little information z StudyStudy nearbynearby galaxiesgalaxies – Light not resolved in individual stars – Objects large and bright: internal structure – Infer evolution through archaeology z StudyStudy resolvedresolved stellarstellar populationspopulations – Ages, metallicities and motions of stars – Archaeology of Milky Way (and nearest neighbors) HSTHST andand E/S0E/S0 galaxiesgalaxies z GiantGiant andand normalnormal E/S0sE/S0s – Distinct central luminosity profiles – Cores, cusps, and central dips z NuclearNuclear disksdisks (gas/dust/stars)(gas/dust/stars) z STISSTIS spectroscopyspectroscopy ⇒⇒ blackblack holehole massesmasses z NuclearNuclear andand globalglobal propertiesproperties correlatecorrelate SpectroscopySpectroscopy Seven elliptical galaxies from the SAURON survey Velocity fields: stellar motions reveal disks and decoupled cores Maps of magnesium line strength: age and metal abundance of stars StructureStructure ofof E/S0E/S0 GalaxiesGalaxies z OblateOblate fastfast rotatorsrotators (E(E && S0)S0) – High specific angular momentum – Embedded stellar disk – Can be strongly anisotropic – Generally steep luminosity cusp (km/s) Fast rotator (NGC 4660) z WeaklyWeakly triaxialtriaxial slowslow rotatorsrotators (E)(E) – Some central rotation, but negligible specific angular momentum – Not necessarily strongly anisotropic – Generally shallow luminosity cusp (km/s) Slow rotator (NGC 4458) Emsellem et al 2007, Cappellari et al 2007, MNRAS, and Falcón-Barroso talk FastFast RotatorsRotators Stellar velocvelocityity field i=20° i=46° i=79° z Stellar kinematics resembles that of disk z Embedded in nearly stationary spheroid/bulge KinematicKinematic structurestructure onon allall scalesscales NGC 4382 McDermid et al., 2006, MNRAS, 373, 906 z SAURON:SAURON: globalglobal kinematicskinematics andand lineline--strengthsstrengths z OASIS:OASIS: spatialspatial resolution:resolution: zoomzoom--inin onon nucleusnucleus z AllowsAllows studystudy ofof orbitalorbital structurestructure nearnear centralcentral BHBH z STIS:STIS: eveneven sharper,sharper, butbut incompleteincomplete viewview BulgesBulges inin SpiralSpiral GalaxiesGalaxies F606W, F160W & F110W StructureStructure ofof SmallestSmallest BulgesBulges z HSTHST revealedrevealed largelarge nuclearnuclear complexitycomplexity inin latelate--typetype spiralsspirals z ManyMany ~exponential~exponential stellarstellar densitydensity profilesprofiles z TheseThese ‘‘bulgesbulges’’ maymay bebe disksdisks (e.g. Kormendy 1993) z ManyMany havehave nuclearnuclear starstar clustercluster z FormationFormation mechanismmechanism unclearunclear Carollo et al. 1997-2007; Böker, van der Marel et al. VelocityVelocity dispersiondispersion dropsdrops NGC 4245 NGC 4274 NGC 4314 z ~50%~50% ofof SaSa--ScSc spirals:spirals: centralcentral minimumminimum inin σσ z TheseThese ‘‘bulgesbulges’’ areare centralcentral disksdisks z RangeRange ofof starstar formationformation historieshistories Falcón-Barroso et al. 2006; Ganda et al. 2006, Peletier et al. 2007, MNRAS NatureNature ofof BulgesBulges z BulgesBulges seemseem toto bebe twotwo componentcomponent systemssystems – Slow-rotating, spheroidal, R1/4, old – Fast-rotating, disk-like, exponential, star forming z WhenWhen diskdisk--likelike componentcomponent dominatesdominates – Exponential profile – Velocity dispersion drop z VarietyVariety ofof starstar formationformation historieshistories – HST multi-color studies (WFPC2/NICMOS/ACS Carollo et al. 2007) – SAURON line strength measurements IonizedIonized GasGas inin E/S0sE/S0s z >75%>75% ofof E/S0sE/S0s havehave extendedextended emissionemission--lineline gasgas – Narrow-band imaging Macchetto et al. 1996, AAS, 120, 463 – SAURON spectroscopy Sarzi et al. 2006, MNRAS, 366, 1151 – Detection rate: S0: 83%, E: 66% – Drops to 55% in Virgo cluster (3/9 E’s) z GasGas distributiondistribution andand kinematicskinematics isis diversediverse – Includes non-axisymmetric motions – Gas origin cannot be purely external or internal z WideWide rangerange ofof [OIII]/H[OIII]/Hβ amongamong andand withinwithin galaxiesgalaxies SomeSome ExamplesExamples Sarzi et al. 2006, MNRAS, 366, 1151 NuclearNuclear IonizedIonized GasGas z ProminentProminent inin activeactive nucleinuclei andand bulgesbulges – ~20% have regular dust disks – Hα, [NII] kinematics (FOS, FOC, STIS) resolves region where black hole dominates, but is often irregular z HSTHST observedobserved overover 100100 objectsobjects – Up to ~100 Mpc distance – ~20% ~fitted by circular rotation ⇒ black hole masses M87M87 FOCFOC Macchetto et al. 1997 CentralCentral GasGas DiskDisk inin NGCNGC 33793379 HHαα alongalong 3 STIS slitsslits Shapiro et al. 2006, MNRAS, 370, 559 TheThe BlackBlack HoleHole inin NGCNGC 33793379 (E1)(E1) z MMBH fromfrom stellarstellar motionsmotions andand fromfrom gasgas kinematicskinematics z RegularRegular centralcentral gasgas diskdisk – Three parallel STIS slits – Gas motions not circular – Twisted model consistent z StellarStellar kinematicskinematics – SAURON: low spatial resolution: upper limit on MBH – OASIS: lower limit on MBH, insufficient field of view – Combination: FOV and resolution: accurate MBH z MassesMasses consistentconsistent Shapiro et al. 2006, MNRAS, 370, 559 TheThe BlackBlack HoleHole inin NGCNGC 821821 (E6)(E6) z DifferentDifferent datadata setssets – SAURON + STIS – Long-slit + STIS z IndependentIndependent codescodes – Nukers, Valluri & Leiden group – Different orbit sampling – Different regularization – Different regularization Gebhardt McDermid z GoodGood agreementagreement – MBH statistical error smaller when 2D McDermid et al. 2007 kinematics used NuclearNuclear OrbitalOrbital StructureStructure Cusp Adiabatic black hole growth Core Merritt 2004 Black hole merger BinaryBinary blackblack holehole mergersmergers expectedexpected toto resultresult inin tangentiallytangentially biasedbiased orbitsorbits insideinside corecore radiusradius Quinlan & Hernquist 1997 ObservedObserved OrbitalOrbital DistributionsDistributions Radial rc orbits Pred. Tangential orbits z NearlyNearly isotropicisotropic velocityvelocity distributiondistribution atat largelarge radiiradii z IsotropicIsotropic (N821)(N821) oror radialradial (M87)(M87) motionmotion insideinside corecore z SimilarSimilar resultsresults forfor otherother giantgiant ellipticalsellipticals ((inclincl N3379)N3379) z NotNot formedformed byby binarybinary--blackblack holehole merger?merger? MMBHBH fromfrom StellarStellar KinematicsKinematics z BHBH massesmasses forfor ~25~25 E/S0E/S0 galaxiesgalaxies andand bulgesbulges – Based on one STIS slit, and ~2 ground-based slits – MBH accuracy can be improved by using integral-field data; this also provides accurate M/L’s and inclinations – Possible for all nearby E/S0s in HST/STIS archive z LimitationsLimitations – Only for bright nearby nuclei – Modest spatial resolution at Virgo (0.2'' slit) – Not enough S/N for core galaxies in Virgo: these are targets for AO-assisted IFU’s on 8m groundbased telescopes (e.g. SINFONI on VLT) BlackBlack HoleHole DemographicsDemographics z EllipticalsEllipticals – Be careful with masses from gas kinematics – Need stellar kinematics for core galaxies (8m) z SpiralsSpirals – Not many masses, 7 especially < 4x10 M~ – Late type disks: no BH? z ScatterScatter – Observational errors Ferrarese & Ford 2005 – Systematics (triaxiality, asymmetries) – Related to merger history? GalaxiesGalaxies withoutwithout BlackBlack HolesHoles z M33M33 andand NGCNGC 205205 – Central star cluster – No AGN – Strong upper limit on black hole mass z IfIf theythey havehave aa BH,BH, thenthen itsits massmass isis wellwell belowbelow thethe (M(MBH,,σσ)) relationrelation Valluri et al. 2005, ApJ 628, 137 TheThe FutureFuture WHT z IncreasedIncreased resolutionresolution needed:needed: – Zooming in on nuclei & more distant objects z AdaptiveAdaptive opticsoptics – Natural guide star: few objects – Increased sky coverage with laser z NucleiNuclei – Integral-field spectroscopy
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