Pollina, Giorgia
(2014)
Properties of cosmic voids in dark energy simulations.
[Laurea magistrale], Università di Bologna, Corso di Studio in
Astrofisica e cosmologia [LM-DM270]
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Abstract
The last decade has witnessed the establishment of a Standard Cosmological
Model, which is based on two fundamental assumptions: the first one is the
existence of a new non relativistic kind of particles, i. e. the Dark Matter
(DM) that provides the potential wells in which structures create, while the
second one is presence of the Dark Energy (DE), the simplest form of which
is represented by the Cosmological Constant Λ, that sources the acceleration
in the expansion of our Universe. These two features are summarized by the
acronym ΛCDM, which is an abbreviation used to refer to the present Standard
Cosmological Model.
Although the Standard Cosmological Model shows a remarkably successful
agreement with most of the available observations, it presents some longstanding
unsolved problems. A possible way to solve these problems is represented
by the introduction of a dynamical Dark Energy, in the form of the
scalar field ϕ. In the coupled DE models, the scalar field ϕ features a direct
interaction with matter in different regimes.
Cosmic voids are large under-dense regions in the Universe devoided of
matter. Being nearby empty of matter their dynamics is supposed to be dominated
by DE, to the nature of which the properties of cosmic voids should
be very sensitive.
This thesis work is devoted to the statistical and geometrical analysis of
cosmic voids in large N-body simulations of structure formation in the context
of alternative competing cosmological models. In particular we used the
ZOBOV code (see ref. Neyrinck 2008), a publicly available void finder algorithm, to
identify voids in the Halos catalogues extraxted from CoDECS simulations
(see ref. Baldi 2012 ). The CoDECS are the largest N-body simulations to
date of interacting Dark Energy (DE) models. We identify suitable criteria to
produce voids catalogues with the aim of comparing the properties of these
objects in interacting DE scenarios to the standard ΛCDM model, at different
redshifts.
This thesis work is organized as follows: in chapter 1, the Standard Cosmological
Model as well as the main properties of cosmic voids are intro-
duced. In chapter 2, we will present the scalar field scenario. In chapter 3 the
tools, the methods and the criteria by which a voids catalogue is created are
described while in chapter 4 we discuss the statistical properties of cosmic
voids included in our catalogues. In chapter 5 the geometrical properties of
the catalogued cosmic voids are presented by means of their stacked profiles.
In chapter 6 we summarized our results and we propose further developments
of this work.
Abstract
The last decade has witnessed the establishment of a Standard Cosmological
Model, which is based on two fundamental assumptions: the first one is the
existence of a new non relativistic kind of particles, i. e. the Dark Matter
(DM) that provides the potential wells in which structures create, while the
second one is presence of the Dark Energy (DE), the simplest form of which
is represented by the Cosmological Constant Λ, that sources the acceleration
in the expansion of our Universe. These two features are summarized by the
acronym ΛCDM, which is an abbreviation used to refer to the present Standard
Cosmological Model.
Although the Standard Cosmological Model shows a remarkably successful
agreement with most of the available observations, it presents some longstanding
unsolved problems. A possible way to solve these problems is represented
by the introduction of a dynamical Dark Energy, in the form of the
scalar field ϕ. In the coupled DE models, the scalar field ϕ features a direct
interaction with matter in different regimes.
Cosmic voids are large under-dense regions in the Universe devoided of
matter. Being nearby empty of matter their dynamics is supposed to be dominated
by DE, to the nature of which the properties of cosmic voids should
be very sensitive.
This thesis work is devoted to the statistical and geometrical analysis of
cosmic voids in large N-body simulations of structure formation in the context
of alternative competing cosmological models. In particular we used the
ZOBOV code (see ref. Neyrinck 2008), a publicly available void finder algorithm, to
identify voids in the Halos catalogues extraxted from CoDECS simulations
(see ref. Baldi 2012 ). The CoDECS are the largest N-body simulations to
date of interacting Dark Energy (DE) models. We identify suitable criteria to
produce voids catalogues with the aim of comparing the properties of these
objects in interacting DE scenarios to the standard ΛCDM model, at different
redshifts.
This thesis work is organized as follows: in chapter 1, the Standard Cosmological
Model as well as the main properties of cosmic voids are intro-
duced. In chapter 2, we will present the scalar field scenario. In chapter 3 the
tools, the methods and the criteria by which a voids catalogue is created are
described while in chapter 4 we discuss the statistical properties of cosmic
voids included in our catalogues. In chapter 5 the geometrical properties of
the catalogued cosmic voids are presented by means of their stacked profiles.
In chapter 6 we summarized our results and we propose further developments
of this work.
Tipologia del documento
Tesi di laurea
(Laurea magistrale)
Autore della tesi
Pollina, Giorgia
Relatore della tesi
Scuola
Corso di studio
Ordinamento Cds
DM270
Parole chiave
Cosmology, Dark Energy, Voids
Data di discussione della Tesi
14 Marzo 2014
URI
Altri metadati
Tipologia del documento
Tesi di laurea
(NON SPECIFICATO)
Autore della tesi
Pollina, Giorgia
Relatore della tesi
Scuola
Corso di studio
Ordinamento Cds
DM270
Parole chiave
Cosmology, Dark Energy, Voids
Data di discussione della Tesi
14 Marzo 2014
URI
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