Astronomers have detected a stealthy black hole because of its effects on a cloud of interstellar gas. This mid-mass black hole is one of more than 100 million silent black holes that should be hiding in the galaxy. These results provide a new method for searching for other hidden black holes and help us understand the growth and evolution of black holes.
Black holes are objects of such gravity that nothing, including light, can escape once fallen beyond the event horizon. Because black holes do not emit light, astronomers must deduce their existence from the effects of their gravity on other objects. The mass of black holes varies from about five times that of the sun to supermassive black holes, millions of times greater than that of the sun. Astronomers believe that small black holes merge and grow progressively, but no one has ever found a black hole of intermediate mass weighing hundreds or thousands of times the mass of the sun.
A research team led by Shunya Takekawa at the National Astronomical Observatory of Japan noticed HCN-0.009-0.044, a gas cloud moving strangely near the center of the galaxy 25,000 light-years from Earth in the constellation of Sagittarius. They used ALMA (Atacama Large Millimeter / Submillimeter Array) to perform high-resolution observations of the cloud and discovered that it was swirling around a huge invisible object.
According to Takekawa, "detailed kinematic analyzes revealed that a huge mass, 30,000 times greater than that of the sun, was concentrated in a region much smaller than our solar system." This, together with the lack of any object observed there strongly suggests an intermediate mass black, and by analyzing other abnormal clouds, we hope to expose other quiet black holes. "
Tomoharu Oka, Keio University professor and team leader, adds, "It is significant that this mid-mass black hole was discovered only 20 light-years away from the supermassive black hole of the galactic center. supermassive, a bit like gas is currently falling in. This reinforces the model of melting black hole growth. "
These results were published in Takekawa et al. "Indication of another black hole of intermediate mass in the galactic center" in Letters from the Astrophysical Journal January 20, 2019.
Image: Prime of the black hole captured in the center of the Milky Way
Shunya Takekawa et al, Indication of another black hole of intermediate mass at the galactic center, The astrophysical journal (2019). DOI: 10.3847 / 2041-8213 / aafb07