Derived electron fraction in the region. Left: map of the electron fraction, X(e). The map shows a smooth distribution but with a clear enhancement in the northwest section. The beam size and scale bar are shown in the top left and bottom right, respectively. The contours correspond to the Herschel-based H₂ column map; the contours are the same as in Fig. 2. Right: Kernel density estimate of the X(e) distribution across the mapped region. A typical value (median of the log₁₀) of 10^−6.5 was derived from these measurements and is marked with a red dashed vertical line.