Bottom: Horologium, top: Auriga. Spectral index γ(v_LSR) (green) compared with the WNM fraction T_WNM(v_LSR) /T_{WNM + CNM}(v_LSR) derived from LAB (pink) and EBHIS Gaussians (red). An upper limit for the Doppler temperature of the CNM of T_D< 1100 K, corresponding to a turbulent CNM Mach number of M_T = 3.7 was applied. For comparison we display the WNM fraction T_WNM(v_LSR) /T_{WNM + CNM}(v_LSR) for a Doppler temperature of T_D< 3900 K, corresponding to a turbulent CNM Mach number of M_T = 7.7 (blue).