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Superclusters%20as%20future%20

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Future of structure in CDM cosmology. Spherical collapse, gravitational binding ... Cosmology. Initially matter-dominated: hierarchical growth of structure ... – PowerPoint PPT presentation

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Title: Superclusters%20as%20future%20


1
Superclusters as future island universes
the case of Shapley
  • Andreas Reisenegger
  • PUC / ESO

Theory/simulations Rolando Dünner (PUC) Andrés
Meza (UChile/UNAB) Pablo A. Araya (Groningen)
Observations Hernán Quintana (PUC) Dominique
Proust (Meudon) E. Rodrigo Carrasco (Gemini)
several others
2
Outline
  • Superclusters, Shapley
  • Superclusters?
  • Future of structure in ?CDM cosmology
  • Spherical collapse, gravitational binding
  • Redshift-space appearance
  • Supercluster boundaries masses
  • Future plans

3
F
2MASS Galactic chart
4
Shapley Supercluster Redshift catalog of Proust
et al. 2006
5
Shapley Supercluster Redshift catalog of Proust
et al. 2006
6
(No Transcript)
7
Superclusters?
  • What is a supercluster?
  • What are its boundaries?
  • So far, definitions have been
  • Vague agglomeration of galaxies or clusters, or
  • Arbitrary some overdensity, or
  • Very technical largest non-percolating
    structures.
  • NOT physical

8
?CDM Cosmology
  • Initially matter-dominated
  • hierarchical growth of structure
  • up to clusters of galaxies (so far)
  • Now, ? is taking over
  • expansion accelerates! (supernovae)
  • bound structures separate from each other
  • structure formation stops
  • Some structures are dense enough to locally
    dominate over ?, but not yet virialized
  • will collapse within the next Hubble time or so
  • largest bound structures in the Universe
  • physical definition of superclusters

9
Pablo A. Araya, PhD Thesis (Groningen), in
preparation
10
Present (a1)
Distant future (a100)
Pablo A. Araya, PhD Thesis (Groningen), in
preparation
11
Spherical model
  • Equation of motion for a mass shell
  • Analytical solution for the critical
    (marginally bound) shell (Dünner et al. 2006,
    MNRAS, 366, 803)

12
Spherical overdensity criterion vs. simulations
  • 28
  • 72
  • 0.26

Dünner et al. 2006
13
Radial velocity profile
Dünner et al. 2006
14
Real space vs. redshift space
Dünner et al., submitted (astro-ph/0611435)
15
Bound structures in redshift space
  • Radial velocity from
  • true density profile (solid)
  • NFW density profile (dashed)
  • simulation (dots boundgreen, unboundblue)

Velocity envelopes derived through spherical
collapse from density profiles of simulated
structures
Dünner et al., submitted (astro-ph/0611435)
16
Redshift-space boundary
  • Shape is velocity envelope from
  • True density profile (black, solid)
  • NFW profile spherical collapse (dashed, red
    green)
  • Calibrate redshift-space density through
    simulations to be able to fit to observed data

Dünner et al., submitted (astro-ph/0611435)
17
The boundaries of Shapley
Dünner et al., in preparation
18
Supercluster masses
Pablo A. Araya, PhD Thesis (Groningen), in
preparation
Dünner et al., in preparation
19
Near future
  • Verify spherical collapse model through Dn-?
    distances to individual clusters in Shapley
    (Magellan proposal Quintana, Reisenegger,
    Melnick, Selman, ...).
  • Claimed disagreement of predicted vs. observed
    supercluster mass function (Einasto et al. 2006)
    verify through redshift-space analysis of
    simulations vs. SDSS or 2dFGRS.
  • Improve compare mass determination methods in
    simulations in Shapley.
  • Center for the Exploration of Superclusters of
    Galaxies (CESGA) Milenio proposal, in 2nd
    round of evaluation.
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