2014/03/31 by Rodrigo von Marttens, R. F. vom Marttens, Wiliam S. Hipólito-Ricaldi +3 · 1 citation
Physics and Astronomy · #Astrophysics #Baryon #Black Holes and Theoretical Physics #Cosmology #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Physics #Theoretical physics #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2014/08/004
published as JCAP08(2014)004 · 22 pages, 6 figures Analysis enlarged, references added, accepted for publication in JCAP
arxiv created 2014/07/04 · openalex publication_date 2014/08/01 · arxiv updated 2014/09/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We consider the perturbation dynamics for the cosmic baryon fluid and determine the corresponding power spectrum for a Λ( t )CDM model in which a cosmological term decays into dark matter linearly with the Hubble rate. The model is tested by a joint analysis of data from supernovae of type Ia (SNIa) (Constitution and Union 2.1), baryonic acoustic oscillations (BAO), the position of the first peak of the anisotropy spectrum of the cosmic microwave background (CMB) and large-scale-structure (LSS) data (SDSS DR7). While the homogeneous and isotropic background dynamics is only marginally influenced by the baryons, there are modifications on the perturbative level if a separately conserved baryon fluid is included. Considering the present baryon fraction as a free parameter, we reproduce the observed abundance of the order of 5% independently of the dark-matter abundance which is of the order of 32% for this model. Generally, the concordance between background and perturbation dynamics is improved if baryons are explicitly taken into account.