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Mapping the kinematics and stellar populations of E/S0s with SAURON

Mapping the kinematics and stellar populations of E/S0s with SAURON. Harald Kuntschner Crete, 12 th August 2004. Outline. Introduction The SAURON survey Results from Kinematics Stellar populations with focus on environmental effects Conclusions. The SAURON team.

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Mapping the kinematics and stellar populations of E/S0s with SAURON

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  1. Mapping the kinematics and stellar populations of E/S0s with SAURON Harald Kuntschner Crete, 12th August 2004

  2. Outline • Introduction • The SAURON survey • Results from • Kinematics • Stellar populations with focus on environmental effects • Conclusions

  3. The SAURON team PIs: Bacon, Davies, de Zeeuw COIs: Bureau, Cappellari, Emsellem, Falcón-Barroso, Krajnović, Kuntschner, McDermid, Peletier plus associated members … http://www.strw.leidenuniv.nl/sauron

  4. Galaxyformation SAURON • When and how do E/S0/Sa galaxies form? • What is the orbital make-up of E/S0s? • What is the average age and metal content? • Origin of substructures; e.g. faint disks in Es, decoupled cores, etc. • E  S0  Sa transformations? • What is the relationship between global properties and super-massive black holes ?

  5. The SAURON project • Systematic study of a representative sample of 48 nearby E/S0s and 24 Sa-type spirals • Wide fieldintegral-field spectroscopy from the ground (SAURON) • Central high spatial sampling integral-field spectroscopy with OASIS/GMOS • HST imaging (and some STIS spectroscopy) • Large scale ground based imaging de Zeeuw et al, 2002, MNRAS, 329, 513

  6. The sample selection • Uniformly covering the ellipticity vs MB plane • MB  -18 mag (factor of 50 in luminosity) • 24 E, 24 S0, 24 Sa (each 12 cluster, 12 field) • cz < 3000 km/s • DEC: -6° < d < +64° and |b|  15°

  7. Why integral-field spectroscopy? Velocity curve Long slit Velocity field Integral field Galaxy Image

  8. Status of the SAURON survey • Observations completed in April 2002 • 8 runs on William Herschel Telescope (4m) • 35.5/56 clear nights • ~200.000 independent galaxy spectra • All data homogeneously reduced • Analysis and interpretation ongoing • 5 refereed papers in 2004 so far

  9. Emsellem et al., 2004, MNRAS, 352, 721 48 E/S0 – DSS images

  10. E S0 S0 S0 E S0 E S0 S0 S0 S0 E S0 S0 S0 S0 E S0 E S0 S0 S0 S0 E S0 E E S0 S0 S0 S0 S0 E E E E 40% classified by RC3 as ellipticals SAURON-classified rotators

  11. SAURON-classified ellipticals E E E S0 E E E E E E E E General agreement with RC3

  12. Results from the kinematic maps • Two classes of early-type galaxies • Flattened rotating lenticulars (some with bars) • Triaxial ellipticals (many kinematically decoupled components) • Discontinuous transition NGC 4660 NGC 4458

  13. Line-strength: Age, Z, [Mg/Fe] • Wavelength covers H, Fe5015, [OIII], Mgb & Fe5270 • Lick/IDS index definitions (+ SAURON adjustments) • Indices + Models can be used to estimate luminosity weighted age, Z and abundance ratios.

  14. N Kinematics and line-Strengths E NGC 4374 NGC 4660 NGC 4365 NGC 4546 NGC 4570 NGC 4406 NGC 4382 I V Mgb Fe

  15. Stellar population models Vazdekis (1999) models at Lick resolution (~8.4 Å FWHM) based on Jones (1999) library Goal: Estimate the luminosity weighted age, metallicity and abundance ratios. [MgFe52]=(Mgb x Fe5270)^0.5

  16. Central Re/8 measurements Traditional RC3 morphologies Mostly old Es Weak evidence for young stellar populations in some field Es S0s in all environs spread to younger ages

  17. Central Re/8 measurements New “morphologies” based on 2-dim kinematics 7 triaxial Es in field only 4 triaxial Es in cluster

  18. V [MgFe50] Hβ Age map Z map NGC 5198 (E; field)

  19. V [MgFe50] Hβ Age map Z map NGC 4150 (S0; cluster)

  20. V [MgFe50] Hβ Age map Z map NGC 4570 (S0; cluster)

  21. A bar in NGC 4570van den Bosch & Emsellem (1998) Metal lines Age map

  22. V [MgFe50] Hβ Age map Z map NGC 4382 (S0; cluster)

  23. Statistics – young populations • 19/48 (40%) of our sample show some evidence of “young” (<10Gyr) stellar populations in the central regions • E cluster: 1/12 • E field: 4/12 E total: 5/24 • S0 cluster: 7/12 • S0 field: 7/12 S0 total: 14/24

  24. Conclusions • SAURON provides 2-dim kinematics and line-strength for 48 nearby E/S0 • Kinematics • Many RC3 classified Es show strong rotation; we suggest new classification in triaxial Es and rotators • Line-strength • Connection between ‘disk-like’ kinematics and enhanced Mgb line-strength (not seen so clearly in Fe lines!) • Evidence for secular, bar-driven evolution in S0s young pops rotation connection in some galaxies • As many as 40% of E/S0 galaxies show signs of young stellar populations mostly in the central regions • Only weak evidence for environmental effects in our sample

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