Researchers from Hiroshima University have shown how gravity alters the shape of matter near to the black hole located in binary system Cygnus X-1. These findings should help other scientists to understand the physics of strong gravity as well as providing new insights into the evolution of black holes.
The black hole was discovered in 1964 during a rocket flight. It has one of the strongest X-ray sources seen from Earth, with a mass about 14.8 times the mass of our Sun. A black hole is a region of spacetime that exhibits such a powerful gravitational effects that nothing, not even particles or light, can escape from inside it.
The Cygnus X-1 black hole is also one of the brightest sources of X-rays in space. The geometry of matter that produces such intensity of light has long puzzled astronomers. The research team have now revealed the source, using new technology.
Conventional filters are not appropriate to view the light because hard X-rays and gamma rays coming from sources near the black hole penetrate conventional filters. To overcome this the researchers launched an X-ray polarimeter on a balloon called PoGO+. A polarimeter is a specialized instrument designed to measure the polarization of light, and for determining the effect of a substance in rotating the plane of polarization of light.
Through the analysis the researchers established that the corona of the black hole is larger and spread around the vicinity of the black hole. Through such information the researchers can uncover more information about black holes, such as their spin.
The effects of black hole spin can alter space-time surrounding the black hole, which is linked to the evolution of the black hole. Analysis may reveal a slowing down in speed since the beginning of the universe, or, alternatively, through the accumulation of matter a black hole will spin faster.
The research is published in the journal Nature Astronomy, with the peer reviewed research paper titled “Accretion geometry of the black-hole binary Cygnus X-1 from X-ray polarimetry.”
