Universe is Teeming with Quintillions of Stellar-Mass Black Holes

---

The formation and evolution of black holes in the Universe is one of the major issues to be addressed by the modern research in astrophysics and cosmology.

In the mass range between 5 and 150 solar masses, black holes are originated from the final, often dramatic stages in the evolution of massive stars.

At the other end, in the range between 106 and 1010 solar masses, supermassive black holes grow mainly by gaseous accretion that energizes the spectacular broadband emission of active galactic nuclei. Such an activity can have a profound impact on galaxy evolution.

The intermediate-mass range between 103 and 106 solar masses is the most uncertain. So far, only tentative evidence of these systems has been identified. However, the chase is open in view of their astrophysical relevance.

News Source