Large-scale periodicity in the distribution of QSO absorption-line systems

TL;DR

This study identifies a periodic pattern in the distribution of QSO absorption-line systems over large scales, suggesting an imprint of early Universe galaxy clustering.

Contribution

It reports the discovery of a regular periodicity in ALS distribution with a specific spatial scale, based on an updated catalog and analysis of metallic systems.

Findings

Periodic distribution with Delta eta = 0.036 +/- 0.002

Corresponds to a spatial scale of 108 +/- 6 h^{-1} Mpc

Indicates possible imprint of early Universe galaxy clustering

Abstract

The spatial-temporal distribution of absorption-line systems (ALSs) observed in QSO spectra within the cosmological redshift interval z = 0.0--4.3 is investigated on the base of our updated catalog of absorption systems. We consider so called metallic systems including basically lines of heavy elements. The sample of the data displays regular variations (with amplitudes ~ 15 -- 20%) in the z-distribution of ALSs as well as in the eta-distribution, where eta is a dimensionless line-of-sight comoving distance, relatively to smoother dependences. The eta-distribution reveals the periodicity with period Delta eta = 0.036 +/- 0.002, which corresponds to a spatial characteristic scale (108 +/- 6) h(-1) Mpc or (alternatively) a temporal interval (350 +/- 20) h(-1) Myr for the LambdaCDM cosmological model. We discuss a possibility of a spatial interpretation of the results treating the pattern obtained as a trace of an order imprinted on the galaxy clustering in the early Universe.