Do the tails of galaxy flux distributions vary spatially in a way that standard cosmology cannot explain? Using the public Euclid ERO photometric catalogues (216,805 sources, three independent fields separated by 160°), we show that they do. The Hill estimator reveals an inter-cell dispersion σ(α) = 0.060–0.087, exceeding 500 MICE2 ΛCDM realisations by 2–5× (p < 0.002). The signal survives ten independent robustness tests, replicates across VIS and NIR-Y bands over four geographically separated fields, and is reproduced by none of the standard N-body realisations. The sharpest signature — r(α̂, Fmed) = −0.79 versus −0.01 in MICE2 — points to a higher-order property of the large-scale matter distribution that current HOD models fail to capture. No new physics is claimed. A robust, fully reproducible statistical anomaly is documented, with 23 deposited scripts and fully open data. The Euclid DR2 data release, expected in October 2026, will provide the decisive test.
Michel DEBAILLEUL (Sat,) studied this question.