  Most common formation channels of stellar mass black hole (BH) binaries like
the ones observed by LIGO, often assume they are assembled from the direct
collapse of massive pre-supernova stars. However, it is still unclear whether
the final mass and spin of the newly formed BH arises from the collapse of the
entire stellar progenitor or just a fraction of it, given that coupling of
accretion feedback released during BH formation to the surrounding infalling
star will inevitably lead to its ejection. If the BH is built up via disk
accretion, outflows from the center will result in residual gas ejection, thus
halting the stellar collapse and reducing the amount of mass and spin that can
be accreted by the newly formed BH. Here we discuss the general properties of
BHs (mass and spin) associated with the collapse of rotating, helium star
pre-supernova progenitors. When accretion feedback is included, the BH drives
powerful outflows that heat the surrounding envelope, effectively shutting down
the collapse. This gives rise to various outcomes ranging from very massive BHs
with low spins, as inferred for GW150914, to lighter and faster-spinning BHs,
as deduced for GW151226.
