Determine the origin of black holes in solar mass and the connection with dark matter

What is the origin of black holes and how does the question relate to another mystery, the nature of dark matter? Dark matter consists of the majority of matter in the universe, but its nature remains unknown.

Several gravitational wave detections of fusing black holes have been identified within the past few years by the Laser Interferometer Gravitational-Wave Observatory (LIGO), commemorating with the 2017 Nobel Prize in Physics to Kip Thorne, Barry Barish and Rainer Weiss. A definitive confirmation of the existence of black holes was celebrated with the 2020 Nobel Prize in Physics awarded to Andrea Ghez, Reinhard Genzel and Roger Penrose. The concept of the origin of black holes thus emerged as a central issue in physics.

Surprisingly, LIGO recently observed a 2.6 solar mass candidate for the solar mass (event GW190814, reported in Astrophysical Journal Letters 896 (2020) 2, L44). Suppose it is a black hole and not an extraordinarily massive neutron star, where does it come from?

Black mass black holes are particularly intriguing, as they are not expected by conventional star physics for stellar evolution. Such black holes can originate in the early universe (primordial black holes) or be “transmuted” from existing neutron stars. Some black holes may have formed in the early universe long before the stars and galaxies formed. Such primordial black holes can form part or all of the dark material. When a neutron star captures an original black hole, the black hole digests the neutron star from within and turns it into a black hole of the solar mass. This process can produce a population of black holes in solar mass, no matter how small the primordial black holes are. Other forms of dark matter can accumulate in a neutron star and cause the eventual collapse into a black hole of the solar mass.

A new study, published in Physical overview letters, conducts a crucial test to investigate the origin of black holes in solar mass. This work was led by the Kavli Institute for Physics and Mathematics of the Universe (Kavli IPMU) Fellow Volodymyr Takhistov and the international team led by George M. Fuller, Senior Professor of Physics and Director of the Center for Astrophysics and Space Science at the University included. from California, San Diego, as well as Alexander Kusenko, professor of physics and astronomy at the University of California, Los Angeles and a visiting senior scientist from Kavli IPMU.

As the study discusses (see Fig. 1), “transmuted” black masses of solar mass remaining from neutron stars devoured by dark matter (tiny earplugs or accumulation of particles of dark matter) must follow the mass distribution of the original host. neutron star. Since the distribution of the neutron star mass is expected to peak at about 1.5 solar masses, heavier solar masses are unlikely to have formed black holes from dark matter that interact with neutron stars. This suggests that such events as the candidate detected by LIGO, if indeed black holes, may be of original origin from the early Universe and thus may drastically affect our understanding of astronomy. Future observations will use this test to investigate and identify the origin of black holes.

Previously (see Fuller, Kusenko, Takhistov Physical overview letters 119 (2017) 6, 061101), the same international team of researchers also showed that disruption of neutron stars through small primordial black holes can lead to a rich variety of observational signatures and help us to understand such years of astronomical mysteries as the origin. of heavy elements (e.g. gold and uranium) and the 511 keV gamma ray excess observed from the center of our Milky Way.

Provided by Kavli Institute for Physics and Mathematics of the Universe