Two different inversions of the gas pressure, P_g(z), for the penumbral pixel highlighted in Fig. 1 by a red square. Left column, from top to bottom: Stokes I, Q, U, and V for the simulated case (𝕀^syn(λ) solid-black lines) and for the two inversions ( solid-red lines and dashed-blue lines) with fixed and “different from the simulated case” temperatures: T₁(z) and T₂(z), respectively. Right column: thermodynamic parameters (synthetic X^syn(z) and inverted X′(z)) of the various models, following the same color code. Upper panel: horizontal line for each model atmosphere (following the same color code) with ticks for, from left to right, the heights at which lgτ₅ = 0, −1, −2, −3.