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Identifier |
000428250 |
Title |
Turnaround radius of galaxy clusters in N-body simulations |
Alternative Title |
Μελέτη της ακτίνας διαφυγής σμηνών γαλαξιών σε προσομοιώσεις Ν-σωμάτων |
Author
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Κορκίδης, Γεώργιος Μ.
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Thesis advisor
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Παυλίδου, Βασιλική
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Reviewer
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Τάσσης, Κωνσταντίνος
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Abstract |
We use N-body simulations to examine whether a characteristic turnaround radius, as
predicted from the spherical collapse model in a ΛCDM Universe, can be meaningfully
identified for galaxy clusters, in the presence of full three-dimensional effects. For that
purpose we use The Dark Sky Simulations and Illustris-TNG dark-matter--only
cosmological runs to calculate radial velocity profiles around collapsed structures,
extending out to many times the virial radius R200. There, the turnaround radius can be
unambiguously identified as the largest non-expanding scale around a center of gravity.
We find that:
a) Indeed, a single turnaround scale can meaningfully describe strongly non-spherical
structures.
b) For halos of masses M200 > 1013M⊙, the turnaround radius Rta scales with the
enclosed mass Mta as Mta1/3
, as predicted by the spherical collapse model.
c) The deviation of Rta in simulated halos from the spherical collapse model prediction
is rather insensitive to halo asphericity. Rather, it is sensitive to the tidal forces due
to massive neighbors when such are present.
d) Halos exhibit a characteristic average density within the turnaround scale. This
characteristic density is dependent on cosmology and redshift. For the present
cosmic epoch and for concordance cosmological parameters (Ωm ∼ 0.3; ΩΛ ∼ 0.7)
turnaround structures exhibit an average matter density contrast with the
background Universe of δ ∼ 11. Thus Rta is equivalent to R11 -- in a way analogous
to defining the "virial" radius as R200 -- with the advantage that R11 is shown in this
work to correspond to a kinematically relevant scale in N-body simulations
|
Language |
English |
Subject |
Large-scale structure of universe |
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Μεγάλης δομές στο σύμπαν |
Issue date |
2020-03-27 |
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/0/e/0/metadata-dlib-1581596329-514886-24043.tkl
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Views |
682 |