[ad_1]
In an international collaboration between Japan and Sweden, scientists explained how gravity affects the shape of matter near the black hole in the Cygnus X-1 binary system. Their discoveries, which were published in Nature Astronomy this month, could help scientists better understand the physics of high gravity and the evolution of black holes and galaxies
. star orbiting the first black hole discovered in the universe. Together they form a binary system known as Cygnus X-1. This black hole is also one of the brightest sources of X-rays in the sky. However, the geometry of the material that gives rise to this light was uncertain. The research team has revealed this information through a new technique called X-ray polarimetry.
Taking a picture of a black hole is not easy. On the one hand, it is not yet possible to observe a black hole because the light can not escape it. Rather, instead of observing the black hole itself, scientists can observe the light coming from the material near the black hole. In the case of Cygnus X-1, this material comes from the star that orbited the black hole very closely.
Most of the light we see, like the sun, vibrates in many directions. Polarization filters the light so that it vibrates in one direction. It is thus that polarized snow goggles allow skiers to see more easily where they are coming down the mountain – they work because the filter cuts off the light reflected by the snow.
"It's the same situation with hard x-rays around a black hole," said Hiromitsu Takahashi, an badistant professor at Hiroshima University and co-author of the "However, hard x-rays and gamma rays from the black hole penetrate this filter, there are no" glbades "for these rays, so we need another type special treatment to direct and measure this scattering of light. "19659003] The team had to determine where the light came from and where it was scattering.In order to do these two measurements, they launched a beam polarimeter X on a balloon called PoGO + From there, the team was able to determine what fraction of hard x-rays was reflected on the accretion disk and identify the shape of the material.
Two models competitors describe how matter near a black hole can appear in a binary system such as Cygnus X-1: l e floor lamp and extended model. In the floor lamp model, the crown is compact and closely related to the black hole. The photons bend toward the accretion disk, which results in more reflected light. In the extended model, the crown is larger and extends around the black hole. In this case, the light reflected by the disc is weaker.
As the light did not bend much under the severe gravity of the black hole, the team concluded that the black hole corresponded to the extended crown pattern
. information, researchers can discover more features on black holes. An example is his spin. The effects of spin can change the space-time surrounding the black hole. Spin could also provide clues about the evolution of the black hole. It could slow down in speed since the beginning of the universe, or it could accumulate matter and spin faster.
"The black hole in Cygnus is one of many," Takahashi said. "We would like to study more black holes using X-ray polarimetry, such as those closer to the center of galaxies, perhaps better understanding the evolution of black holes, as well as the evolution of galaxies. . "
by University of Hiroshima . Note: Content can be changed in style and length.
Source link
