Molecular gas and X -ray emission around the Sagittarius A *, the black hole of the Milky Way
Mark D. Gorski et al. (CC by 4.0)
We found a hot wind that explodes for the first time in the supermassive black hole in our galaxy, which could help us understand its mysterious inactivity.
Compared to many other supermassive black holes found in galaxies centers, our black hole, called sagittarius a * or sgr a *, is relatively calm. He does not draw vast powerful jets such as black holes in many other galaxies, which are so brilliant that we can spot them even in the first moments of the universe. But all the supermassive black holes, including SGR A *, produced winds – hot gas wafts exploded near the horizon of the black hole event, where the gas swirls and heats up violently.
These winds, however, have never been detected in a conclusive manner in SGR A *, although they have been planned since the 1970s. It is partly because it is so difficult to observe the region around the black hole in our galaxy, a mixture of stars, dust and well -wrapped gas, called the Circumnuclear disk (CND).
Now Mark Gorski and Elena Muchikova at Northwestern University in Illinois have measured the most interior region of the CND in more detail than before using the large network of millimeters / submillimetrics of Atacama (Alma) in Chile. They found large areas of cold gas, they did not expect to be there, as well as a clear cone of hot gas which cuts it, which seems to be the missing wind.
Find so much cold gas around the black hole at this distance was unexpected, explains Gorski. Conventional wisdom was that it was useless to look for it, because it probably did not exist, he said. “When I presented this image to [my colleague]I said, “Well, we have to focus on this now, because it has been such a problem for over 50 years”. »»
Gorski and Murchikova took five years of observations from the interior part of the Alma CND and produced a cold gas card in a few light years from Sgr A * which was 100 times clearer than previous observations. They reached it by simulating how Sgr’s lively light sparkled, then subtracted from the low light from cold gas.
From that, they could see a clear cone in which there was practically no cold gas. When they threw X -ray data – the emissions produced by hot gas – Overtop, they found the two regions corresponding almost perfectly. They calculated the total energy necessary to blow up the hot gas through this cone equivalent to around 25,000 suns, which means that it cannot have been produced from neighboring stars, and there are also no obvious supernovas that could have generated hot gas either. This suggests that the wind comes from Sgr to * itself. “The necessary energy requires a black hole to be there. There must be a wind of the black hole, ”explains Gorski.
Astronomers previously spotted large gas bubbles above and below the galactic plane, called Fermi bubbles, which suggest that our black hole once had jets. However, it is not clear if these jets could form again. The measurement of this wind could help to explain why Sgr A * is relatively inactive and helping us to better understand the phases of the evolution of black holes.
Finding the missing wind of Sgr A * is exciting if the results are confirmed, explains Ziri Yoursi to the University College of London, because it could give us crucial information on the black hole itself, for example in which direction it runs. Astronomers assumed that Sgr was perpendicular to the plane of the Milky Way, which means that we should see it towards the edge. But when the first images of the black hole in the Horizon Event telescope were published in 2022, it seemed to be facing the place, although the data were not conclusive.
“The mass of sagittarius A * is incredibly well limited by observations, but its angle of inclination compared to us is so badly limited that it can be anything,” explains Yoursi. “Perhaps understand where these flows of matter come from, if this result is absolutely robust, is really exciting because it gives us an indication as to the direction in which the whole problem flows in the black hole arrives.” It could also help us better understand how our galaxy has evolved.
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