Triaxial galaxy models

Triaxial galaxy modelsTriaxial galaxy models

Glenn van de VenGlenn van de Ven

Institute for Advanced Institute for Advanced StudyStudy

[email protected]@ias.edu

Hubble Symposium, March, 2008Hubble Symposium, March, 2008 Glenn van de Ven, "Triaxial galaxy models"Glenn van de Ven, "Triaxial galaxy models"

OutlineOutlineOutlineOutline

• Fast and slow rotators with SAURONFast and slow rotators with SAURON- Paper IX: Emsellem et al. (2007, MNRAS, 379, 401)Paper IX: Emsellem et al. (2007, MNRAS, 379, 401)- Paper X: Cappellari et al. (2007, MNRAS, 379, 418)Paper X: Cappellari et al. (2007, MNRAS, 379, 418)

• Triaxial Schwarzschild modelsTriaxial Schwarzschild models- van de Ven, de Zeeuw & van den Bosch (2008, MNRAS, in van de Ven, de Zeeuw & van den Bosch (2008, MNRAS, in

press)press)- van den Bosch, van de Ven, et al. (2008, MNRAS, in press)van den Bosch, van de Ven, et al. (2008, MNRAS, in press)

• Next steps and summaryNext steps and summary


Integral-field spectroscopyIntegral-field spectroscopyIntegral-field spectroscopyIntegral-field spectroscopy

… … a spectrum at every a spectrum at every position on the plane of the position on the plane of the skysky


SAURON stellar velocity fields SAURON stellar velocity fields 48 48 E/S0sE/S0s

SAURON stellar velocity fields SAURON stellar velocity fields 48 48 E/S0sE/S0s

EE

E EE

E

EEE E

E

E

E

E

E E

E E

E

E

E

E

E

E

40% fast rotators classified as E in RC340% fast rotators classified as E in RC3 Slow rotators


Kinematical misalignmentKinematical misalignmentKinematical misalignmentKinematical misalignmentFast rotatorsSlow rotators

22

VR

VRR

… … simplifiedsimplified

spin spin parameterparameter


Kinematical componentsKinematical componentsKinematical componentsKinematical components

Single component Multiple components Central low velocityKT = Kinematical TwistKM = Kin. MisalignmentKDC = Kin. Decoupled Comp.LV = Low Velocity

NGC 4382

NGC 5813

Fast rotatorsSlow rotators


KDCs: age versus sizeKDCs: age versus sizeKDCs: age versus sizeKDCs: age versus size

Paper VIII: McDermid et al. (2007, MNRAS, 373, Paper VIII: McDermid et al. (2007, MNRAS, 373, 906)906)

Slow rotatorsFast rotators


Understanding the Understanding the V/V/σσ--εε diagram diagramUnderstanding the Understanding the V/V/σσ--εε diagram diagram

• Results consistent Results consistent with with (axisymmetric) (axisymmetric) modeling modeling subsamplesubsample

• Two classes of Two classes of early-type galaxiesearly-type galaxies

• Oblate anisotropic Oblate anisotropic fast-rotatorsfast-rotators

• (Weakly) triaxial (Weakly) triaxial slow-rotatorsslow-rotators

Fast rotators Slow rotators

22

221

R

zδ = 0isotropic

δ = 0.6

i = 90°edge-on

i = 0°

intr22

2

7.02

1

R

z


Image of numerical orbitImage of numerical orbitImage of numerical orbitImage of numerical orbit


images of model orbits observed image

Schwarzschild’s approachSchwarzschild’s approachSchwarzschild’s approachSchwarzschild’s approach

• Surface brightness Surface brightness (MGE) gravitational potential (MGE) gravitational potential

• Grid of (E,IGrid of (E,I22,I,I33) ) initial orbit conditions initial orbit conditions orbit library orbit library

• Weighted superposition of orbits that best fits Weighted superposition of orbits that best fits

photometry photometry andand kinematics kinematics dynamical model dynamical model

Schwarzschild (1979), Richstone & Tremaine (1988), Rix et al. (1997), Schwarzschild (1979), Richstone & Tremaine (1988), Rix et al. (1997), van der Marel (1998), Cappellari et al. (2002), Gebhardt et al. (2003), …van der Marel (1998), Cappellari et al. (2002), Gebhardt et al. (2003), …


Triaxial Schwarzschild modelsTriaxial Schwarzschild modelsTriaxial Schwarzschild modelsTriaxial Schwarzschild models• (MGE) mass model that allows for PA twist in (MGE) mass model that allows for PA twist in

observed SBobserved SB

• (De)projection involves three viewing angles ((De)projection involves three viewing angles (θθ,,,,))

• Four major orbit families:Four major orbit families:

• Robust test with theoretical 3-integral triaxial Abel Robust test with theoretical 3-integral triaxial Abel modelsmodels

2. Inner long-axis tube orbit

3. Outer long-axis tube orbit

4. Short-axis tube orbit

1. Box orbit

x y

z


Application to NGC 4365Application to NGC 4365Application to NGC 4365Application to NGC 4365

V σ h3 h4

Model

Sym

metr

ized

D

ata


Viewing direction and shapeViewing direction and shapeViewing direction and shapeViewing direction and shape

Best-fit (Best-fit (θθ,,,,) = (68) = (68°°,73,73°°,91,91°°) oblate … ) oblate … triaxialtriaxial

T = (1-pT = (1-p22)/(1-q)/(1-q22) )

Oblate: p=1 (a=b>c), T=0Oblate: p=1 (a=b>c), T=0

Prolate: p=q (a>b=c), T=1Prolate: p=q (a>b=c), T=1


Orbital structureOrbital structureOrbital structureOrbital structure

• Dominant prograde and retrograde Dominant prograde and retrograde short-axis tubes nearly cancelshort-axis tubes nearly cancel

• Retrogade long-axis tubes only Retrogade long-axis tubes only ~20% mass, but provide large scale ~20% mass, but provide large scale rotationrotation

• KDC no distinct separate KDC no distinct separate component; no age gradientcomponent; no age gradient


Metallicity and age in NGC 4365Metallicity and age in NGC 4365Metallicity and age in NGC 4365Metallicity and age in NGC 4365

Davies et al. (2001, ApJ, 548, Davies et al. (2001, ApJ, 548, 33)33)


Next stepsNext stepsNext stepsNext steps

• Built-up red sequenceBuilt-up red sequence- Complete sample AtlasComplete sample Atlas3D3D (265 E/S0, M (265 E/S0, MKK≤≤-21.5, D-21.5, D≤41 Mpc≤41 Mpc))- Axisymmetric/Triaxial dynamical models of fast/slow rotatorsAxisymmetric/Triaxial dynamical models of fast/slow rotators- Comparison with (cosmological) simulationsComparison with (cosmological) simulations

• Linking dynamics and stellar populationsLinking dynamics and stellar populations- Comparison using kinemetry Comparison using kinemetry ((Kuntschner et al. 2008, in prep.)Kuntschner et al. 2008, in prep.)- Including colors, ages and metallicities in dynamical modelsIncluding colors, ages and metallicities in dynamical models

• Other modeling applicationsOther modeling applications- Globular clusters Globular clusters (van de Ven et al. 2006, A&A, 445, 513)(van de Ven et al. 2006, A&A, 445, 513)- Dark halo Dark halo (Weijmans et al., 2008, MNRAS, 383, 1343)(Weijmans et al., 2008, MNRAS, 383, 1343)- Spiral galaxies Spiral galaxies (Ganda, van de Ven & Peletier, 2008, in prep.)(Ganda, van de Ven & Peletier, 2008, in prep.)- Gravitational lensing and dynamicsGravitational lensing and dynamics


Summary in figuresSummary in figuresSummary in figuresSummary in figuresSlow rotatorsFast rotators Kinematical misalignment

KDCs

NGC 4365


See also …See also …See also …See also …

http://www.strw.leidenuniv.nl/sauron/

http://www-astro.physics.ox.ac.uk/atlas3d/


Dynamics of Dynamics of Globular ClustersGlobular Clusters

Dynamics of Dynamics of Globular ClustersGlobular Clusters

ωω Centauri Centauri

van de Ven et al. (2006, A&A, 445, 513)


Ionized and cold gasIonized and cold gasIonized and cold gasIonized and cold gas

Weijmans et al. (2008, MNRAS, 383, 1343)

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Triaxial galaxy models