Crete, 1/24

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

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

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The SAURON team

• PIs Bacon, Davies, de Zeeuw
• COIs Bureau, Cappellari, Emsellem,
  Falcón-Barroso, Krajnovic, Kuntschner, McDermid,
  Peletier
• plus associated members
• http//www.strw.leidenuniv.nl/sauron

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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 ?

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The SAURON project

• Systematic study of a representative sample of 48
  nearby E/S0s and 24 Sa-type spirals
• Wide field integral-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
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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 lt 3000 km/s
• DEC -6 lt d lt 64 and b ? 15

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

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48 E/S0 DSS images
Emsellem et al., 2004, MNRAS, 352, 721
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SAURON-classified rotators
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SAURON-classified ellipticals
E
E
E
S0
E
E
E
E
E
E
E
E
General agreement with RC3
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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
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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.

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Kinematics and line-Strengths
N
E
NGC 4660
NGC 4374
NGC 4546
NGC 4570
NGC 4406
NGC 4365
NGC 4382
I
V
Mgb
Fe
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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
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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
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Central Re/8 measurements
New morphologies based on 2-dim kinematics
7 triaxial Es in field only 4 triaxial Es in
cluster
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NGC 5198 (E field)
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NGC 4150 (S0 cluster)
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NGC 4570 (S0 cluster)
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A bar in NGC 4570van den Bosch Emsellem (1998)
Metal lines
Age map
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NGC 4382 (S0 cluster)
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Statistics young populations

• 19/48 (40) of our sample show some evidence of
  young (lt10Gyr) 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

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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