Scientists have recently produced the first images of a giant black hole in a galaxy far away but there is a supermassive black hole much closer to home. At the center of our own galaxy lies an invisible monster, whose gravity can help maintain the milky way. We can not see this black hole, but the observations have detected some of its effects as a sphere of overheated gas. A new study has now revealed the flip side, a relatively cold gas ring around the black hole.
This black hole, known as Sagittarius A * (pronounced "Sagittarius A Star") is about 26 000 light-years away from Earth. It is difficult to observe because you have to look through the Milky Way disk, but observations have shown that this region of space is populated by stars, nebulae, and hot and cold clouds of gas. The gas must form a rotating accretion disk that extends over several tenths of a light year from the horizon of the black hole events.
Previously, all we could see, it is the hot part of this gas via millimeter wave observations, which gives an incomplete picture of the effects of the black hole in the near space. All scientists have been able to say before that there was a component of cold gas, but we now have a faithful image.
Of course, the term "cold" is a relative term here. The hot gases around Sagittarius A * are about 10 million degrees Celsius, which is two-thirds of the temperature of the solar core. This gas emits X-rays, one of the distinctive signs of a black hole. In comparison, cold hydrogen only reaches 10,000 degrees Celsius (18,000 degrees Fahrenheit). The researchers used Atacama's Large Millimeter / Submilleter Array (ALMA) system to look for the low radio frequency of this colder gas ring.
The resulting image (top) shows the flow of cold gas around Sagittarius A *. The mapping of the Doppler shift in the spectrum as the gas was moving towards us and moving away from us revealed a ring structure. The red part moves away from the Earth and the blue part goes to the Earth. The team said this ring of gas extended to one hundredth of a light year from the event horizon (about 1,000 times the distance from the Earth to the sun).
These data could provide new information on how black holes consume material in the vicinity. I hope this is something we will never have to worry about on Earth, but it can help us understand what is happening in other parts of the world. universe.