### Abstract

The BOSS quasar sample is used to study cosmic homogeneity with a 3D survey in the redshift range 2.2 < z < 2.8. We measure the count-in-sphere, N(< r), i.e. the average number of objects around a given object, and its logarithmic derivative, the fractal correlation dimension, D _{2} (r). For a homogeneous distribution N(< r) r ^{3} and D _{2} (r) = 3. Due to the uncertainty on tracer density evolution, 3D surveys can only probe homogeneity up to a redshift dependence, i.e. they probe so-called "spatial isotropy». Our data demonstrate spatial isotropy of the quasar distribution in the redshift range 2.2 < z < 2.8 in a model-independent way, independent of any FLRW fiducial cosmology, resulting in 3-D _{2} < 1.7 × 10 ^{-3} (2 σ) over the range 250 < r < 1200 h ^{-1} Mpc for the quasar distribution. If we assume that quasars do not have a bias much less than unity, this implies spatial isotropy of the matter distribution on large scales. Then, combining with the Copernican principle, we finally get homogeneity of the matter distribution on large scales. Alternatively, using a flat ΛCDM fiducial cosmology with CMB-derived parameters, and measuring the quasar bias relative to this ΛCDM model, our data provide a consistency check of the model, in terms of how homogeneous the Universe is on different scales. D _{2} (r) is found to be compatible with our ΛCDM model on the whole 10 < r < 1200 h ^{-1} Mpc range. For the matter distribution we obtain 3-D _{2} < 5 × 10 ^{-5} (2 σ) over the range 250 < r < 1200 h ^{-1} Mpc, consistent with homogeneity on large scales.

Original language | English (US) |
---|---|

Article number | 060 |

Journal | Journal of Cosmology and Astroparticle Physics |

Volume | 2016 |

Issue number | 11 |

DOIs | |

State | Published - Nov 30 2016 |

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### All Science Journal Classification (ASJC) codes

- Astronomy and Astrophysics

### Cite this

*Journal of Cosmology and Astroparticle Physics*,

*2016*(11), [060]. https://doi.org/10.1088/1475-7516/2016/11/060

}

*Journal of Cosmology and Astroparticle Physics*, vol. 2016, no. 11, 060. https://doi.org/10.1088/1475-7516/2016/11/060

**A.** / Laurent, Pierre; Goff, Jean Marc Le; Burtin, Etienne; Hamilton, Jean Christophe; Hogg, David W.; Myers, Adam; Ntelis, Pierros; Pâris, Isabelle; Rich, James; Aubourg, Eric; Bautista, Julian; Delubac, Timothée; Bourboux, Hélion Du Mas Des; Eftekharzadeh, Sarah; Delabrouille, Nathalie Palanque; Petitjean, Patrick; Rossi, Graziano; Schneider, Donald P.; Yeche, Christophe.

Research output: Contribution to journal › Article

TY - JOUR

T1 - A

AU - Laurent, Pierre

AU - Goff, Jean Marc Le

AU - Burtin, Etienne

AU - Hamilton, Jean Christophe

AU - Hogg, David W.

AU - Myers, Adam

AU - Ntelis, Pierros

AU - Pâris, Isabelle

AU - Rich, James

AU - Aubourg, Eric

AU - Bautista, Julian

AU - Delubac, Timothée

AU - Bourboux, Hélion Du Mas Des

AU - Eftekharzadeh, Sarah

AU - Delabrouille, Nathalie Palanque

AU - Petitjean, Patrick

AU - Rossi, Graziano

AU - Schneider, Donald P.

AU - Yeche, Christophe

PY - 2016/11/30

Y1 - 2016/11/30

N2 - The BOSS quasar sample is used to study cosmic homogeneity with a 3D survey in the redshift range 2.2 < z < 2.8. We measure the count-in-sphere, N(< r), i.e. the average number of objects around a given object, and its logarithmic derivative, the fractal correlation dimension, D 2 (r). For a homogeneous distribution N(< r) r 3 and D 2 (r) = 3. Due to the uncertainty on tracer density evolution, 3D surveys can only probe homogeneity up to a redshift dependence, i.e. they probe so-called "spatial isotropy». Our data demonstrate spatial isotropy of the quasar distribution in the redshift range 2.2 < z < 2.8 in a model-independent way, independent of any FLRW fiducial cosmology, resulting in 3-D 2 < 1.7 × 10 -3 (2 σ) over the range 250 < r < 1200 h -1 Mpc for the quasar distribution. If we assume that quasars do not have a bias much less than unity, this implies spatial isotropy of the matter distribution on large scales. Then, combining with the Copernican principle, we finally get homogeneity of the matter distribution on large scales. Alternatively, using a flat ΛCDM fiducial cosmology with CMB-derived parameters, and measuring the quasar bias relative to this ΛCDM model, our data provide a consistency check of the model, in terms of how homogeneous the Universe is on different scales. D 2 (r) is found to be compatible with our ΛCDM model on the whole 10 < r < 1200 h -1 Mpc range. For the matter distribution we obtain 3-D 2 < 5 × 10 -5 (2 σ) over the range 250 < r < 1200 h -1 Mpc, consistent with homogeneity on large scales.

AB - The BOSS quasar sample is used to study cosmic homogeneity with a 3D survey in the redshift range 2.2 < z < 2.8. We measure the count-in-sphere, N(< r), i.e. the average number of objects around a given object, and its logarithmic derivative, the fractal correlation dimension, D 2 (r). For a homogeneous distribution N(< r) r 3 and D 2 (r) = 3. Due to the uncertainty on tracer density evolution, 3D surveys can only probe homogeneity up to a redshift dependence, i.e. they probe so-called "spatial isotropy». Our data demonstrate spatial isotropy of the quasar distribution in the redshift range 2.2 < z < 2.8 in a model-independent way, independent of any FLRW fiducial cosmology, resulting in 3-D 2 < 1.7 × 10 -3 (2 σ) over the range 250 < r < 1200 h -1 Mpc for the quasar distribution. If we assume that quasars do not have a bias much less than unity, this implies spatial isotropy of the matter distribution on large scales. Then, combining with the Copernican principle, we finally get homogeneity of the matter distribution on large scales. Alternatively, using a flat ΛCDM fiducial cosmology with CMB-derived parameters, and measuring the quasar bias relative to this ΛCDM model, our data provide a consistency check of the model, in terms of how homogeneous the Universe is on different scales. D 2 (r) is found to be compatible with our ΛCDM model on the whole 10 < r < 1200 h -1 Mpc range. For the matter distribution we obtain 3-D 2 < 5 × 10 -5 (2 σ) over the range 250 < r < 1200 h -1 Mpc, consistent with homogeneity on large scales.

UR - http://www.scopus.com/inward/record.url?scp=85065654898&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85065654898&partnerID=8YFLogxK

U2 - 10.1088/1475-7516/2016/11/060

DO - 10.1088/1475-7516/2016/11/060

M3 - Article

AN - SCOPUS:85065654898

VL - 2016

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

SN - 1475-7516

IS - 11

M1 - 060

ER -