Scalar perturbations in the late Universe: viability of the Chaplygin gas models

Journal Article · Tue Dec 01 04:00:00 EST 2015 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2015/12/037· OSTI ID:22525119

Bouhmadi-López, Mariam ^[1]; Brilenkov, Maxim; Brilenkov, Ruslan ^[2]; Morais, João ^[3]; Zhuk, Alexander ^[4]

---

1. Departamento de Física, Universidade da Beira Interior, 6200 Covilhã (Portugal)
2. Department of Theoretical Physics, Odessa National University, Dvoryanskaya st. 2, Odessa 65082 (Ukraine)
3. Department of Theoretical Physics, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao (Spain)
4. Astronomical Observatory, Odessa National University, Dvoryanskaya st. 2, Odessa 65082 (Ukraine)

We study the late-time evolution of the Universe where dark energy (DE) is parametrised by a modified generalised Chaplygin gas (mGCG) on top of cold dark matter (CDM) . We also take into account the radiation content of the Universe. In this context, the late stage of the evolution of the universe refers to the epoch where CDM is already clustered into inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies). Under these conditions, the mechanical approach is an adequate tool to study the Universe deep inside the cell of uniformity. To be more accurate, we study scalar perturbations of the Friedmann-Lemaȋtre-Robertson-Walker metric due to inhomogeneities of CDM as well as fluctuations of radiation and mGCG, the later driving the late-time acceleration of the universe. Our analysis applies as well to the case where mGCG plays the role of DM and DE . We select the sets of parameters of the mGCG that are compatible with the mechanical approach. These sets define prospective mGCG models. By comparing the selected sets of models with some of the latest observational data results, we conclude that the mGCG is in tight agreement with those observations particularly for a mGCG playing the role of DE and DM.

• OSTI ID: 22525119
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 12 Vol. 2015; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCELERATION
COMPARATIVE EVALUATIONS
COSMIC GASES
DISTURBANCES
EVOLUTION
FLUCTUATIONS
GALAXIES
GALAXY CLUSTERS
METRICS
NONLUMINOUS MATTER
SCALARS
UNIVERSE