Is the Cosmic Transparency Spatially Homogeneous?

TL;DR

This paper investigates the spatial variation of cosmic transparency using recent BAO and SNIa data, finding oscillating best-fit opacity values across different redshift ranges, but overall consistent with a transparent universe within 1σ confidence.

Contribution

It provides the first detailed analysis of redshift-dependent cosmic opacity constraints using the latest observational data.

Findings

Best-fit cosmic opacity varies with redshift, indicating possible spatial inhomogeneity.

Results are consistent with a transparent universe at 1σ confidence level.

Opacity oscillates between zero and nonzero values across redshift ranges.

Abstract

We study the constraints on the cosmic opacity using the latest BAO and Union2 SNIa data in this paper and find that the best fit values seem to indicate that an opaque universe is preferred in redshift regions $0.20-0.35$, $0.35-0.44$ and $0.60-0.73$, whereas, a transparent universe is favored in redshift regions $0.106-0.20$, $0.44-0.57$and $0.57-0.60$. However, our result is still consistent with a transparent universe at the 1$\sigma$ confidence level, even though the best-fit cosmic opacity oscillates between zero and some nonzero values as the redshift varies.