Stellar-Mass Black Holes and Their Progenitors

Understand

If a black hole has a low spin value, it must double its mass to reach a high spin parameter.

• Although this is easily accomplished through mergers or accretion in the case of supermassive black holes in galactic centers, it is impossible for stellar-mass black holes in X-ray binaries.
• Thus, the spin distribution of stellar-mass black holes is almost pristine, largely reflective of the angular momentum imparted at the time of their creation.
• This fact can help provide insights on two fundamental questions: What is the nature of the central engine in supernovae and gamma-ray bursts? and What was the spin distribution of the first black holes in the universe?