Accretion Feedback from newly-formed black holes and its implications for LIGO Sources

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.