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Identifier |
000459427 |
Title |
Turnaround density as a probe of the dark energy equation of state |
Alternative Title |
Η πυκνότητα αναστροφής ως διαγνωστικό μέσο για την εξίσωση κατάστασης της σκοτεινής ενέργειας |
Author
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Κυβερνητάκη-Σινάνη, Άννα Ν.
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Thesis advisor
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Παυλίδου, Βασιλική
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Reviewer
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Ζέζας, Ανδρέας
Νιάρχος, Βασίλειος
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Abstract |
Turnaround density probes cosmology. In other words, the matter density within the turnaround radius of a large-scale structure depends on cosmology. So far, it has been shown, both through spherical collapse calculations and through N-body simulations, that measurements of the turn-around density can probe both the matter and dark energy density parameters. These calculations assumed that dark energy had the form of a cosmological constant. They showed the turnaround density is particularly sensitive to the halting of structure growth imparted by a cosmological constant or, alternatively, dark energy. In this thesis, we study how different equations of state of dark energy affect the turnaround density, and whether we can use observations of turnaround density in galaxy clusters to constrain the dark energy equation of state. We do so within the context of the spherical collapse model. We explore both clustering and non-clustering dark energy, and in particular we study the sensitivity of the evolution of the turnaround density on the value of w which parameterizes the dark energy equation of state, in each of the two cases. We find that the behavior of the turnaround density with time is qualitatively similar in all the cases studied (converging for high redshift; decreasing at low redshift). However, they are different enough for the turnaround density to act as a meaningful probe of the dark energy equation of state. Interestingly, we also find no-go regimes for turnaround in the case of non-clustering dark energy, or even cases where structures disintegrate after turnaround, consistent with "big rip" scenarios.
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Language |
English |
Subject |
Cosmology |
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Large-scale structure |
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Δομές μεγάλης κλίμακας |
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Κοσμολογία |
Issue date |
2023-11-22 |
Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/e/2/4/metadata-dlib-1697270436-23970-3304.tkl
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Views |
967 |