  Massive Pop III stars can die as energetic supernovae that enrich the early
universe with metals and determine the properties of the first galaxies. With
masses of about $10^9$ Msun at $z \gtrsim 10$, these galaxies are believed to
be the ancestors of the Milky Way. This paper investigates the impact of Pop
III supernova remnants (SNRs) from both Salpeter-like and top-heavy initial
mass functions (IMFs) on the formation of first galaxies with high-resolution
radiation-hydrodynamical simulations with the ENZO code. Our findings indicate
that SNRs from a top-heavy Pop III IMF produce more metals, leading to more
efficient gas cooling and earlier Pop II star formation in the first galaxies.
From a few hundred to a few thousand Pop II stars can form in the central
regions of these galaxies. These stars have metallicities of $10^{-3}$ to
$10^{-2}$, Zsun, greater than those of extremely metal-poor (EMP) stars. Their
mass function follows a power-law distribution with $dN(M_*)/dM_* \propto
M_*^{\alpha}$, where $M_*$ is stellar mass and $\alpha = 2.66 - 5.83$ and is
steeper for a top-heavy IMF. We thus find that EMP stars were not typical of
most primitive galaxies.
