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The Dark Side of the Universe - E2C3 2012

By Sara Ávila, Aina Márquez, Carlota Corbella, Nieves Montes, Laia Domingo, Elena Muñiz, Pau Mir, Joan Solà, Oriol Frigola, Gerard Orriols, Dra. Katie Mack, Dr. Anastasios Avgoustidis, Dr. Carlos J. A. P. Martins
by

Gerard Orriols

on 18 April 2015

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Transcript of The Dark Side of the Universe - E2C3 2012

A constant energy which fills the space
THE DARK ENERGY
THE DARK MATTER
Strings, monopoles, and domain walls
TOPOLOGICAL DEFECTS IN THE UNIVERSE
The dark side of the
A topological defect is created by a symmetry breaking. We can represent it as follows:
How are they formed?
Symmetry breaking without defects
But in the universe the distances between objects are very large...
Symmetry breaking WITH defects
?
?
Goals:
PROPERTIES
COSMIC
STRINGS
DOMAIN
WALLS
MONOPOLES
Dimensions: 0
Dimensions: 1
Dimensions: 2
CLASSIFICATION
Depending on the way a symmetry is broken, the following
topological defects are formed:
They are energy concentrations with cons-tant density, although the Universe expands.
They are infinite or closed on themselves.
They move at relativistic velocities.
They radiate gravitational waves and so they deform the spacetime.
What is a topological defect?
Topological defects
are irregularities in the energy distribution caused by a sudden phase transition.
INTERACTIONS
.
monopole
.
.
Double Y-junction
Initial state
Intercommuting
No interaction
X-junction
Average distance between walls
Average velocity between walls
Parameters we will obtain
The computer solves the differential equations
We can write this mathematicaly...
SIMULATION I
Radiation era
vs.
Matter era
Radiation era
Matter era
Radiation era
Matter era
Compare the evolution of domain walls for different expansion rates
Compare data from the UNIVERSE supercomputer and our computer
Time
Energy density
Time evolution of the energy density
Time evolution of the velocity of the walls
Velocity of the domain walls
Time
Conclusions:
The velocity of the walls remains constant with time
Redshift &
Blueshift
In radiation era the final speed is a bit higher than in matter era
Density is inversely proportional to time
Andromeda Galaxy (M31)
BLUESHIFT
Goals:
SIMULATION II
Behaviour with different interactions
Compare the evolution of domain walls with different types of interaction: forming X-junctions, Y-junctions or not interacting
Time evolution of the energy density of domain walls
Conclusions:
The velocity and the density are lower when Y-junctions are formed
Virgo Galaxy (M61)
REDSHIFT
Time evolution of the average speed of domain walls
Joves i Ciència presents ...
With the support of
Fundació Catalunya Caixa
Starring professors...
Dr. Anastasios (Tasos) Avgoustidis
Dr. Carlos J. A. P. Martins
Dr. Katherine (Katie) Mack
with the students...
Joan Solà Pau Mir
Carlota Corbella Gerard Orriols
Nieves Montes Laia Domingo
Aina Márquez Oriol Frigola
Sara Avila Elena Muñiz
Goals:
SIMULATION III
3D Universe
vs.
4D Universe
Conclusions:
Supernovae
Observe the effect of having extra dimensions on the evolution of walls
Evolution of energy density as a function of time
4D
ΛCDM
3D
The Universe is not expanding at a constant rate
Compare the results of compact and infinite universes
80 x 80 x 80 x ...
Despite changing the size of the fourth dimension (making it compact), domain walls always tend to have a constant velocity and their density also decreases uniformly.
Fritz Zwicky
Vera Rubin
We add Dark Matter to the galaxies
FINAL CONCLUSIONS
It works!
We consider several Universes

Independently of the initial conditions and the parameters that we choose, domain walls tend to an
attractor solution
.
We need more matter!
Dark matter
Separated by the Asymptotic Velocity
79 Galaxies
9 groups
Likelihood
Applied to a group of galaxies
Parameters
∑ = disk central surface density (M /pc )
o
The and parameters are related to the curvature and the formation of loops and we will find them
with our simulations
rc = Dark Matter core radius (kpc)
ρ = Dark matter core density (M /pc )
o
r = disk scale radius (kpc)
o
Θ
2
3
Θ
The values
of and
are in agreement with
the published ones.
+
Density is always inversely proportional to time, and the velocity becomes a constant in every model.
Possible alternative
explanations
Dades obtingudes de l'article:
Rotation Curves of 967 Spiral Galaxies
Massimo Persic and Paolo Salucci
Keep rockin' delta theta!
The DarkSiders...
A little bit of history...
Universe accelerates with time
t
Dark Matter is necessary to explain the rotation curves of the galaxies.
Galaxies with more total mass have higher rotation curves.
Galaxies are made of a disk with luminous matter and a halo with dark matter.
Conclusions
large distance
Checking probability
Universe
The velocity and the density are greater when X-junctions are formed
Evolution of the velocity as a function of time
Evolution of the velocity as a function of time
Evolution of energy density as a function of time
Fitted parameters:
That strange matter that we cannot see
Luminous matter
Dark matter
Total matter
Full transcript