English

Is there evidence for anomalous dipole anisotropy in the large-scale structure?

Cosmology and Nongalactic Astrophysics 2017-01-23 v3

Abstract

We probe the anisotropy of the large-scale structure (LSS) with the WISE-2MASS catalogue. This analysis is performed by a directional comparison of the galaxy number counts through the entire celestial sphere once systematic effects, such as star-galaxy separation and foregrounds contamination, are properly taken into account. We find a maximal hemispherical asymmetry whose dipolar component is A=0.0507±0.0014A = 0.0507 \pm 0.0014 toward the (l,b)=(323,5)(l,b) = (323^{\circ},-5^{\circ}) direction, whose result is consistent with previous estimations of our proper motion in low and intermediate redshifts, as those carried out with Type Ia Supernovae and similar LSS catalogues. Furthermore, this dipole amplitude is statistically consistent (pp-value = 0.0610.061) with mock catalogues simulated according to the expected Λ\LambdaCDM matter density fluctuations, in addition to observational biases such as the incomplete celestial coverage and anisotropic sky exposure. Our results suggest, therefore, that there is no strong evidence for anomalous anisotropy in the LSS, given the limitations and systematics of current data, in the concordance model scenario.

Keywords

Cite

@article{arxiv.1606.06751,
  title  = {Is there evidence for anomalous dipole anisotropy in the large-scale structure?},
  author = {C. A. P. Bengaly and A. Bernui and J. S. Alcaniz and H. S. Xavier and C. P. Novaes},
  journal= {arXiv preprint arXiv:1606.06751},
  year   = {2017}
}

Comments

8 pages, 4 figures, 1 table, accepted in MNRAS