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arXiv · 2010.05173

Perturbations in a Chaplygin gas Cosmology

Shambel Sahlu·Heba Sami·Anna-Mia Swart·Thato Tsabone·Maye Elmardi·Amare Abebe
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Abstract

In this paper we study the perturbations of a cosmic multi-fluid medium consisting of radiation, dust and a Chaplygin gas. To do so, we follow the 1 + 3 covariant formalism and derive the evolution equations of the fluctuations in the energy density for each species of fluid in the multi-fluid system. The solutions to these coupled systems of equations are then computed in both short-wavelength and long-wavelength modes. Our preliminary results suggest that unlike most dark energy models that discourage large-scale structure formation due to the rapid cosmological expansion (which gives little time for fluctuations to coalesce), the Chaplygin-gas model supports the formation of cosmic structures. This is manifested in the solutions of the perturbation equations which show the growth of density fluctuations over time.

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Shambel Sahlu, Heba Sami, Anna-Mia Swart, Thato Tsabone, Maye Elmardi, Amare Abebe. 2020-10-11. Perturbations in a Chaplygin gas Cosmology. https://arxiv.org/abs/2010.05173

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