In this episode of Space Sparks, ESA / Hubble summarizes their findings.
At times in science when you were trying to find something that you had predicted, instead you found something very different. This was the case recently when astronomers using the Hubble Space Telescope examined the heart of a spherical universe, a “ball” of dense old stars called NGC 6397, looking for one central black hole. large. Instead they suddenly found an all-out swarm of small black holes, as reported by NASA and ESA on February 11, 2021.
There are two types of fixed black holes: the stellar mass black hole that is formed when a large star runs out of fuel and bends and measures just a few times our solar mass, and the a supermassive black hole believed to be in the center of every major galaxy and has a mass of millions of stars. In addition to these two types, astronomers believe that there should be a kind of black hole in the middle of the road – the intermediate level black hole, with a mass of 100 to 100,000 times the mass of our sun – and there are several there are candidates for these but only a few proven cases.
These researchers’ analysis of data from the Hubble Space Telescope and the Gaia Space Observatory on this global clock did not provide the evidence of a medium-sized black hole at its heart that the astronauts were looking for. Instead, they made the first discovery of a collection of black holes in the middle of a global browser.
The NGC 6397 global collection, which contains hundreds of thousands of stars, was designed by the Hubble Space Telescope. The blue stars of the cluster are warmer and near the end of their lives, while the orange ones are the big red stars. The white stars include stars that resemble our sun. Image via NASA / ESA / T. Brown and S. Casertano (STScI).
Astronauts were targeting this particular global group, NGC 6397, because at 7,800 light-years away, it is one of the closest global assemblages to Earth. More importantly, scientists believe that a globular browser is a unique place to find medium-sized black holes because of the dense collection of stars at their hearts.
Earth’s assemblages are large spherical assemblages of stars that move along the periphery of galaxies. The collections are old, sometimes almost as old as the universe itself. A global browser has fallen apart, such as NGC 6397, as one that is old enough that the big stars have gone to the center of the bra, and the youngest stars have traveled out to. attack. This gives the globular body a very dense nucleus.
Since it is not possible to look directly at these black holes, the astronomers measured how the stars in the cluster move – their velocities – to find the orbital orbit in the cluster. The places where stars have been found moving faster are areas where more mass has accumulated. But the distribution of these stars was not limited to one central place similar to the heart, as would be expected from the presence of a central black hole. Instead, the ornament appears to be more randomly distributed, expanding to a few percent of the size of the cluster.
Therefore, based on stellar evolution, the astronomers concluded that the remnants of stars in the form of giant stellar black holes reside in the inner regions of the globular sphere. NGC 6397 could host more than 20 of these, the “lightest” type of black hole.
This artist’s concept shows the density of black holes in the center of the NGC 6397 globe collection. In fact, the black holes are far too small for direct observation with any telescopes out there. This globular group can contain more than 20 black holes. Image via ESA / Hubble / N. Bartmann.
Like much of the scientific discovery, the detection of black holes in a global browser raises more questions, with a key one: could the union of these black holes into dense quarters lead to waves of gravity? Scientists may be able to find out if black holes hit together to remove the cracks in gravity that some instruments have seen recently, and they may find something that they weren’t even planning on.
Bottom line: Astronauts looked for one medium-sized black hole in the middle of a globe browser and instead found a whole bunch of smaller black holes.
Source: Is NGC 6397 a more central black hole or inner subcluster?
Through NASA
Through ESA
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