English

Supernovae anisotropy power spectrum

Cosmology and Nongalactic Astrophysics 2017-10-27 v3

Abstract

We contribute another anisotropy study to this field of research using Type Ia supernovae (SNe Ia). In this work, we utilise the power spectrum calculation method and apply it to both the current SNe Ia data and simulation. Using the Union2.1 data set at all redshifts, we compare the spectrum of the residuals of the observed distance moduli to that expected from an isotropic universe affected by the Union2.1 observational uncertainties at low multipoles. Through this comparison we find a dipolar anisotropy with tension of less that 2σ2\sigma towards l=171±21l =171^\circ \pm 21^\circ and b=26±28b=-26^\circ \pm 28^\circ which is mainly induced by anisotropic spatial distribution of the SNe with z>0.2z > 0.2 rather than being a cosmic effect. Furthermore, we find a tension of 4σ\sim 4\sigma at =4\ell=4 between the two spectra. Our simulations are constructed with the characteristics of the upcoming surveys like the Large Synoptic Survey Telescope (LSST), which shall bring us the largest SNe Ia collection to date. We make predictions for the amplitude of a possible dipolar anisotropy that would be detectable by future SNe Ia surveys.

Keywords

Cite

@article{arxiv.1609.08012,
  title  = {Supernovae anisotropy power spectrum},
  author = {Hoda Ghodsi and Shant Baghram and Farhang Habibi},
  journal= {arXiv preprint arXiv:1609.08012},
  year   = {2017}
}

Comments

15 pages, 7 figures, final version

R2 v1 2026-06-22T16:01:31.535Z