Pristine Inner Galaxy Survey. X.

The interstellar medium in DGs, including Sgr, may have retained yields from more energetic Population III and II supernovae (SNe), thereby reducing the average [C/Fe]. Additionally, SNe Ia producing more Fe than C would start to contribute at lower metallicity in DGs/Sgr than in the Galaxy. The presence of a [C/Fe] gradient for Sgr stars with [Fe/H]>~-2.0 (~6.8x10^-4^dex/ arcmin) suggests that SNe Ia contributed to the system at those metallicities, especially in its inner regions.

There is a low frequency of carbon-enhanced metal-poor (CEMP) stars in our Sgr sample. At higher metallicities and carbon abundances (i.e. mostly CEMPs), this may be due to photometric selection effects, but those are less likely to affect non-CEMP stars. Given the lower average [C/Fe] in DGs, we propose using the same CEMP definition ([C/Fe]>+0.7) as that applied to the Galaxy at large ends up underpredicting the number of CEMP stars in DGs.

Burthermore, for Sgr, a cut at [C/Fe]~+0.35 may be more appropriate, which brings the frequency of CEMP stars in agreement with that of the whole Galaxy.