We present a census of blue horizontal branch ( BHB ) and blue straggler ( BS ) stars belonging to dwarf galaxies and globular clusters , and compare these counts to that of the Milky Way stellar halo .
We find , in agreement with earlier studies , that the ratio of BS-to-BHB stars in these satellite populations is dependent on stellar mass .
Dwarf galaxies show an increasing BS-to-BHB ratio with luminosity .
In contrast , globular clusters display the reverse trend , with N _ { BS } / N _ { BHB } ( \lesssim 1 ) decreasing with luminosity .
The faintest ( L < 10 ^ { 5 } L _ { \odot } ) dwarfs have similar numbers of BS and BHB stars ( N _ { BS } / N _ { BHB } \sim 1 ) , whereas more massive dwarfs tend to be dominated by BS stars ( N _ { BS } / N _ { BHB } \sim 2 - 40 ) .
We find that the BS-to-BHB ratio in the stellar halo is relatively high ( N _ { BS } / N _ { BHB } \sim 5 - 6 ) , and thus inconsistent with the low ratios found in both ultra-faint dwarfs and globular clusters .
Our results favour more massive dwarfs as the dominant “ building blocks ” of the stellar halo , in good agreement with current predictions from \Lambda CDM models .