Using the Very Large Telescope (VLT) From the European Southern Observatory (ESO), a team of astronomers and astronomers discovered a small black hole outside the Milky Way, observing how it influences the motion of a nearby star.
This is the first time this detection method has been used to reveal the presence of a Black Hole outside our galaxy. The technique could hold the key to revealing the presence of hidden black holes in our galaxy or others nearby, shed light on how these mysterious objects form and evolve.
The newly discovered black hole was detected in NGC 1850, a cluster of thousands of stars located about 160,000 light-years away in the Large Magellanic Cloud, a neighboring Milky Way galaxy.
A detective investigation
“We looked at each of the stars in this cluster and, like Sherlock Holmes following in the wrong steps of a criminal gang with his magnifying glass, we tried to find some evidence of the presence of black holes, although without seeing them directly,” he says. Sara Saracino, from the Astrophysical Research Institute of Liverpool John Moores University (United Kingdom), who led this research, accepted for publication in the journal Royal Astronomical Society Monthly Notices.
A small black hole has been discovered in a cluster of stars in the Large Magellanic Cloud, observing how it influences the motion of a nearby orbiting star.
“The result we’ve shown would represent just one of the wanted criminals, but when you find one, you’re on your way to discovering many more in different groups,” he adds.
This first “criminal” tracked down by the team turned out to be approximately 11 times more massive than our Sun. The smoking weapon that put the team on the trail of this black hole was its gravitational influence on the star orbiting five solar masses.
The astronomical community had already detected such small stellar-mass black holes in other galaxies capturing the x-ray glow issued when they swallow matter, or from gravitational waves generated when black holes collide with each other or with neutron stars.
dynamic detection
However, most stellar-mass black holes do not reveal their presence through X-rays or gravitational waves. “The presence of the vast majority only reveals itself in a dynamic way”, he highlights. Stefan Dreizler, a member of the team at the University of Göttingen (Germany), “and when a black hole forms a system with a star, it will affect the star’s motion in a subtle but detectable way, so with sophisticated instruments we will be able to find it. them”.
This dynamic method could allow the astronomical community to detect many more black holes and help uncover their mysteries.
This dynamic method, used by Saracino and his team, could allow the astronomical community to detect many more black holes and help uncover their mysteries. “Each detection we make will be important to our future understanding of star clusters and the black holes in them,” says another author, Mark Gieles, from the University of Barcelona (Spain).
The detection made in NGC 1850 marks the first time that a black hole has been detected in a young star cluster (the cluster is only about 100 million years old, a blink of an eye on an astronomical scale). Using his dynamic method on clusters of similar stars could reveal the presence of even more young black holes and shed new light on how they evolve.
By comparing them to larger, older black holes located in older clusters, the astronomical community could understand how these objects grow by feeding on stars or merging with other black holes. In addition, mapping the demography of black holes into star clusters improves our understanding of the origin of gravitational wave sources.
It is the first time a black hole has been detected in a young star cluster
To carry out its search, the team used data collected over two years with the MUSE instrument (Multi Unit Spectroscopic Explorer) of the VLT, located in the Chilean Atacama Desert.
“UXO allowed us to observe highly populated areas, such as the innermost regions of star clusters, analyzing the light from each of the nearby stars. The net result is information about thousands of stars in a single shot, at least 10 times more than with any other instrument”, says the co-author. sebastian kamann, an expert and veteran of the MUSE instrument at the Liverpool Astrophysical Research Institute.
This allowed the team to detect the strange star whose peculiar movement signaled the presence of the black hole. The data of the Optical gravitational lens experiment of the University of Warsaw (Poland) and the Space Telescope Hubble NASA and ESA allowed them to measure the black hole’s mass and confirm their findings.
Rights: Creative Commons.
.