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Open Astronomy

formerly Baltic Astronomy

Editor-in-Chief: Barbuy, Beatriz

IMPACT FACTOR 2018: 0.350

CiteScore 2018: 0.24

SCImago Journal Rank (SJR) 2018: 0.202
Source Normalized Impact per Paper (SNIP) 2018: 0.144

ICV 2017: 121.03

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Volume 23, Issue 3-4


Improvements in the Spherical Collapse Model and Dark Energy Cosmologies

A. Del Popolo
  • Dipartimento di Fisica e Astronomia, University Of Catania, Viale Andrea Doria 6, 95125 Catania, Italy
  • INFN sezione di Catania, Via S. Sofia 64, I-95123 Catania, Italy
  • International Institute of Physics, Universidade Federal do Rio Grande do Norte, 59012-970 Natal, Brazil
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2017-02-18 | DOI: https://doi.org/10.1515/astro-2017-0181


In the present paper, we study how the effects of deviations from spherical symmetry of a system, produced by angular momentum, and shear stress, influence typical parameters of the spherical collapse model, like the linear density threshold for collapse of the non-relativistic component (δc) and its virial overdensity (ΔV). The study is performed in the framework of the Einstein-de Sitter and ΛCDM models, and assuming that the vacuum component is not clustering within the homogeneous non-spherical overdensities. We start from the standard spherical top hat model (SCM) which does not take account the non-spherical effects, and we add to this model the shear term and angular momentum term, which are finally expressed in terms of the density contrast, δ. We find that the non-spherical terms change the non-linear evolution of the system and that the collapse stops “naturally” at the virial radius, differently from the standard spherical collapse model. Moreover, shear and rotation gives rise to higher values of the linear overdensity parameter and different values of ΔV with respect to the standard spherical collapse model.

Keywords: cosmology: theory; large-scale structure of Universe; dark energy; galaxies: formation


About the article

Received: 2014-10-03

Accepted: 2014-11-07

Published Online: 2017-02-18

Published in Print: 2014-12-01

Citation Information: Open Astronomy, Volume 23, Issue 3-4, Pages 189–198, ISSN (Online) 2543-6376, DOI: https://doi.org/10.1515/astro-2017-0181.

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© 2014 A. Del Popolo, published by De Gruyter Open. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. BY-NC-ND 3.0

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