Cross-correlation of Gaia DR3 Stellar Kinematics with Fermi LAT Gamma-ray Residual and Halo Template: Evidence for Spatial Coincidence up to 19.1σ

We present a cross-correlation analysis between Gaia DR3 stellar halo kinematics and gamma-ray data from Fermi LAT. Original result (v1.0): full-sky GALPROP-subtracted residual (10–50 GeV), Spearman ρ = +0.080 at 3.3σ (CI = 0.041, 0.122). New result (v2.0): using a professionally decomposed 21 GeV halo component map (Totani, priv. comm.; southern sky patch b ∈ −60°, −28°), the correlation strengthens to ρ = +0.194 at 11.6σ. With strict halo star selection (pm > 12 mas/yr, plx < 0.2 mas), ρ = +0.306 at 19.1σ. Disk stars show no correlation (ρ = 0.017). The signal passes rotation, shuffle, and latitude detrending null tests. Limitations: single energy band, partial sky coverage, spatial autocorrelation not corrected. Code and data: https://github.com/olwynamser/dm-halo-cross-correlation