Differential calibration of the effective Gaia DR3 parallax offset using the Tier 1 sample. Left: Gaussian fit (red dashed curve) to the parallax residual Δϖ = ϖ_Gaia − ϖ_phot in the near-field regime d  <  4 kpc (blue histogram); the fitted mean is approximately −14 μas. Right: parallax zero-point offset as a function of G magnitude. The gray scales show the stellar density, the red squares and curves represent the binned median values, and the horizontal dashed line marks the zero level.