2019/08/27 by E. O. Zavarygin, E O Zavarygin, John K. Webb +1 · 4 citations
Physics and Astronomy · #Anisotropy #Astronomy #Astrophysics #Cosmic microwave background #Cosmological principle #Cosmology #Cosmology and Gravitation Theories #Dark energy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Intergalactic medium #Isotropy #Lyman-alpha forest #Physical cosmology #Physics #Planck #Quantum mechanics #Quasar #Radio Astronomy Observations and Technology #Redshift #Sky #Universe #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stz2416
published in Monthly Notices of the Royal Astronomical Society 489(3), 3966-3980 (Oxford University Press) · accepted by MNRAS
arxiv created 2019/08/27 · openalex publication_date 2019/08/30 · arxiv updated 2019/09/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
ABSTRACT The cosmological principle, the combined assumptions of cosmological isotropy and homogeneity, underpins the standard model of big bang cosmology with which we interpret astronomical observations. A new test of isotropy over the redshift range 2 < z < 4 and across large angular scales on the sky is presented. We use the cosmological distribution of neutral hydrogen, as probed by the Ly α forest seen towards distant quasars. The Sloan Digital Sky Survey provides the largest data set of quasar spectra available to date. We use combined information from Data Releases 12 and 14 to select a sample of 142 661 quasars most suitable for this purpose. The scales covered by the data extend beyond post-inflation causality scales, thus probing initial conditions in the early Universe. We identify significant spatially correlated systematic effects that can emulate cosmological anisotropy. Once these systematics have been accounted for, the data are found to be consistent with isotropy, providing an important independent check on the standard model, consistent with results from cosmic microwave background data.