A Testable Hypothesis for Dynamical Dark Energy as a Spatially Propagating Field: Observational Tests and Constraint

This version includes preliminary observational analyses using Planck CMB maps, WISE × SuperCOSMOS galaxy catalogs, SDSS galaxy catalogs, and related cosmological datasets. The analyses include ISW tomography, directional anisotropy tests, harmonic-space CMB–galaxy cross-correlation measurements, redshift slicing, multipole localization, galaxy-position randomization, jackknife stability tests, and robustness checks involving Galactic masking and mask apodization.

The observational program did not identify robust evidence for a cosmological-scale preferred axis, anisotropic expansion pattern, or propagating dark-energy front, thereby placing initial constraints on the simplest detectable forms of the proposed framework. However, the analyses did identify a localized low-redshift CMB–galaxy cross-correlation anomaly in the southern sky. The feature is independently reproduced in both WISE × SuperCOSMOS and SDSS galaxy samples and persists across the SMICA, NILC, SEVEM, and Commander Planck component-separation maps. The anomaly's physical origin remains unknown, and the results should be regarded as exploratory pending independent confirmation, formal look-elsewhere corrections, and further analysis using additional large-scale-structure datasets.

DOI: https://doi.org/10.5281/zenodo.20546797