Morphology and dynamics of the cosmic web

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Morphology and dynamics of the cosmic web
Cosmic Voids Amsterdam, 2006
Miguel Angel Aragon-Calvo Rien v.d.
Weygaert Bernard Jones Thijs v.d. Hulst
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• Gravity naturally gives rise to
• Walls
• Filaments
• Clusters
• Voids

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Characterizing the morphological components of
the cosmic web The Multiscale Morphology
Filter (MMF) (A small review)
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Study the morphological information in a density
field
Where
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The Hessian Matrix
The eigenvalues of the Hessian matrix encode
shape information, i.e. how the field changes
locally
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How do we account for the multiscale nature of
the LSS?
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Recovering the underlying density field
(DTFE) W. Schaap Rien v. d. Weygaert

• Advantages
• Follows scale
• Preserves original structure. Does not introduce
  artifacts
• Volume filling

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• Disadvantages
• Linear interpolation
• Smoothing length must be larger than delaunay
  triangle-tetrahedra.

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MMF Main procedure
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Small test with Voronoi models

• Galaxies located at the vertices of voronoi cells
  (clusters), joined by edges resembling filaments
  which define planes (walls)

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Application to a LCDM model
Particle distribution
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Density Field
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The cosmic web seen with the MMF
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Inventory of the cosmic web
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Density of the cosmic web
Voids
Walls
Filaments
Blobs
Density alone can not separate the morphological
components!!!
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• Studying the cosmic web in more detail
• Properties of
• Filaments
• Walls

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Compressing filaments and walls The spine of the
cosmic web
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Density profiles
Filaments
Walls
Walls define the boundaries of voids!!!
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But the Universe is not static
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The cosmic web is shaped by its Dynamics
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Clusters of galaxies The nodes of the cosmic web
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Clusters of galaxies The nodes of the cosmic web
(in time)
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Dynamics of haloes in filaments
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Dynamics of haloes in filaments
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Walls
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Walls
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And Voids
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And Voids
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Dynamics of the cosmic web traced by dark matter
haloes
Peculiar velocities
Filaments
Walls
Flowing with the filament
And along the wall
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Peculiar velocities as function of distance from
the spine of the cosmic web
Filaments
Walls
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Peculiar velocities in time
Zeldovich pancacke?
Walls
Filaments
Dynamical environment determines the interaction
between haloes and their surroundings
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Some properties of haloes in the cosmic web
Mass function
Haloes (FoF)
Subhaloes (FracHop)
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Formation time of haloes in the cosmic web
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Formation times as function of morphology, mass
and density
All densities
0ltdeltalt10
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Orientation of haloes in the cosmic web
Aragon-Calvo et al 2006, in press
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Evolution of orientations in the cosmic web
Inertia tensor
Filaments
Walls
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Evolution of orientations in the cosmic web
Spin Vector
Filaments
Walls
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Conclusions

• Advertisement
• We developed a method (MMF) that characterizes
  the morphological components of the matter
  distribution Blobs, Filaments Walls and Voids,
  allowing us to obtain a Qualitative and
  Quantitative description of the Large Scale
  Structure.
• The cosmic Web
• The dynamics of the cosmic web are closely
  related to its morphology. In fact, they shape
  it.
• Environment plays a crucial role in the
  determination of the properties of haloes not
  only in terms of their local density but by
  defining a dynamical environment which determines
  the interaction between haloes and its
  surroundings and with other haloes.