Predicted density maps of [C/Fe] versus [Fe/H] for stellar populations inhabiting the MW halo. The different panels and colors highlight the contributions of various Pop III SN types: faint, core-collapse, high-energy, and hypernovae. The gray continuous lines represent the predictions of the homogeneous model without the contribution of Pop III SNe, for different rotation velocities of Pop II massive stars (v_rot = 0, 150, and 300 km s⁻¹, Limongi & Chieffi 2018). Data (symbols, see figure legend) are from Mucciarelli et al. (2022), Yong et al. (2013), and Amarsi et al. (2019). Empty symbols represent upper limits.