# Baryonic matter perturbations in decaying vacuum cosmology

## Abstract

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.

- Authors:

- Departamento de Física, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Campus de Goiabeiras, CEP 29075-910, Vitória, Espírito Santo (Brazil)
- Departamento de Ciências Naturais, Universidade Federal do Espírito Santo, CEUNES, Rodovia BR 101 Norte, km. 60, CEP 29932-540, São Mateus, Espírito Santo (Brazil)

- Publication Date:

- OSTI Identifier:
- 22373426

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 08; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; BARYONS; COSMOLOGY; DATA ANALYSIS; NONLUMINOUS MATTER; OSCILLATIONS; PEAKS; PERTURBATION THEORY; RELICT RADIATION; SPECTRA

### Citation Formats

```
Marttens, R.F. vom, Zimdahl, W., and Hipólito-Ricaldi, W.S., E-mail: rodrigovonmarttens@gmail.com, E-mail: wiliam.ricaldi@ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br.
```*Baryonic matter perturbations in decaying vacuum cosmology*. United States: N. p., 2014.
Web. doi:10.1088/1475-7516/2014/08/004.

```
Marttens, R.F. vom, Zimdahl, W., & Hipólito-Ricaldi, W.S., E-mail: rodrigovonmarttens@gmail.com, E-mail: wiliam.ricaldi@ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br.
```*Baryonic matter perturbations in decaying vacuum cosmology*. United States. doi:10.1088/1475-7516/2014/08/004.

```
Marttens, R.F. vom, Zimdahl, W., and Hipólito-Ricaldi, W.S., E-mail: rodrigovonmarttens@gmail.com, E-mail: wiliam.ricaldi@ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br. Fri .
"Baryonic matter perturbations in decaying vacuum cosmology". United States.
doi:10.1088/1475-7516/2014/08/004.
```

```
@article{osti_22373426,
```

title = {Baryonic matter perturbations in decaying vacuum cosmology},

author = {Marttens, R.F. vom and Zimdahl, W. and Hipólito-Ricaldi, W.S., E-mail: rodrigovonmarttens@gmail.com, E-mail: wiliam.ricaldi@ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br},

abstractNote = {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.},

doi = {10.1088/1475-7516/2014/08/004},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 08,

volume = 2014,

place = {United States},

year = {Fri Aug 01 00:00:00 EDT 2014},

month = {Fri Aug 01 00:00:00 EDT 2014}

}