# Can the cosmological constant be mimicked by smooth large-scale inhomogeneities for more than one observable?

## Abstract

As an alternative to dark energy it has been suggested that we may be at the center of an inhomogeneous isotropic universe described by a Lemaitre-Tolman-Bondi (LTB) solution of Einstein's field equations. In order to test such an hypothesis we calculate the low redshift expansion of the luminosity distance D{sub L}(z) and the redshift spherical shell mass density mn(z) for a central observer in a LTB space without cosmological constant and show how they cannot fit the observations implied by a ΛCDM model if the conditions to avoid a weak central singularity are imposed, i.e. if the matter distribution is smooth everywhere. Our conclusions are valid for any value of the cosmological constant, not only for Ω{sub Λ} > 1/3 as implied by previous proofs that q{sup app}{sub 0} has to be positive in a smooth LTB space, based on considering only the luminosity distance. The observational signatures of smooth LTB matter dominated models are fundamentally different from the ones of ΛCDM models not only because it is not possible to reproduce a negative apparent central deceleration q{sup app}{sub 0}, but because of deeper differences in their space-time geometry which make impossible solve the inversion problem when more than onemore »

- Authors:

- Yukawa Institute for Theoretical Physics and Physics Department, Kyoto University, Kyoto 606-8502 (Japan)

- Publication Date:

- OSTI Identifier:
- 22272882

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Cosmology and Astroparticle Physics

- Additional Journal Information:
- Journal Volume: 2010; Journal Issue: 05; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; ASTROPHYSICS; COSMOLOGICAL CONSTANT; COSMOLOGY; EINSTEIN FIELD EQUATIONS; GEOMETRY; LUMINOSITY; MATHEMATICAL SOLUTIONS; NONLUMINOUS MATTER; RED SHIFT; SINGULARITY; SPACE-TIME; UNIVERSE

### Citation Formats

```
Romano, Antonio Enea, E-mail: aer@yukawa.kyoto-u.ac.jp.
```*Can the cosmological constant be mimicked by smooth large-scale inhomogeneities for more than one observable?*. United States: N. p., 2010.
Web. doi:10.1088/1475-7516/2010/05/020.

```
Romano, Antonio Enea, E-mail: aer@yukawa.kyoto-u.ac.jp.
```*Can the cosmological constant be mimicked by smooth large-scale inhomogeneities for more than one observable?*. United States. doi:10.1088/1475-7516/2010/05/020.

```
Romano, Antonio Enea, E-mail: aer@yukawa.kyoto-u.ac.jp. Sat .
"Can the cosmological constant be mimicked by smooth large-scale inhomogeneities for more than one observable?". United States. doi:10.1088/1475-7516/2010/05/020.
```

```
@article{osti_22272882,
```

title = {Can the cosmological constant be mimicked by smooth large-scale inhomogeneities for more than one observable?},

author = {Romano, Antonio Enea, E-mail: aer@yukawa.kyoto-u.ac.jp},

abstractNote = {As an alternative to dark energy it has been suggested that we may be at the center of an inhomogeneous isotropic universe described by a Lemaitre-Tolman-Bondi (LTB) solution of Einstein's field equations. In order to test such an hypothesis we calculate the low redshift expansion of the luminosity distance D{sub L}(z) and the redshift spherical shell mass density mn(z) for a central observer in a LTB space without cosmological constant and show how they cannot fit the observations implied by a ΛCDM model if the conditions to avoid a weak central singularity are imposed, i.e. if the matter distribution is smooth everywhere. Our conclusions are valid for any value of the cosmological constant, not only for Ω{sub Λ} > 1/3 as implied by previous proofs that q{sup app}{sub 0} has to be positive in a smooth LTB space, based on considering only the luminosity distance. The observational signatures of smooth LTB matter dominated models are fundamentally different from the ones of ΛCDM models not only because it is not possible to reproduce a negative apparent central deceleration q{sup app}{sub 0}, but because of deeper differences in their space-time geometry which make impossible solve the inversion problem when more than one observable is considered, and emerge at any redshift, not only for z = 0.},

doi = {10.1088/1475-7516/2010/05/020},

journal = {Journal of Cosmology and Astroparticle Physics},

issn = {1475-7516},

number = 05,

volume = 2010,

place = {United States},

year = {2010},

month = {5}

}