Scientists have long thought that galaxies evolved first, while the black holes at their centers formed after massive stars collapsed. However, recent comments from the web tell a different story. The telescope found evidence for the first ever evolving supermassive black holes with no host galaxy.
The Webb observation may finally provide an answer to an astronomical chicken-or-egg question, suggesting that ancient black holes did not need to consume large amounts of surrounding gas and dust to grow to their enormous size.
“This is a remarkable discovery,” Roberto Maillino, a researcher at the University of Cambridge and co-author of two studies published in Nature and the Monthly Notices of the Royal Astronomical Society, said in a NASA statement. “This is a paradigm shift, a complete revision of the classical scenarios of how black holes form and grow.”
a look back in time
One of the first tiny glowing bits of infrared light that Webb found was named Abell2744-QSO1 (QSO1), It is exactly 700 million years after the Big Bang (5% of its present age). The prototypical Little Red Dot is gravitationally lensed by the galaxy cluster Abell 2744. This makes it an ideal target, as it appears larger and three times larger.
Initial observations of QSO1 revealed that it may A supermassive black hole approximately 40 million times the mass of the Sun, surrounded by a cloud of glowing hydrogen and helium gas. However, scientists couldn’t be sure whether the black hole was really that massive.
“Before now, all mass measurements of black holes in the early universe were indirect, based on assumptions about what we know about them in the local universe. We didn’t know whether those assumptions actually applied to the distant universe,” Francesco D’Eugenio, a researcher at the University of Cambridge and co-author of the study, said in a statement.
weighing the animal
To confirm the black hole’s mass, the team behind the study explored the effect of its gravity on the gas swirling around it and mapped the distribution of different elements in the gas. Using Webb’s Near Infrared Spectrograph (NIRSpec), scientists found that the gas orbits a central point in the same way that the planets in our solar system orbit the Sun. This phenomenon is known as Keplerian motion.
“This is important because it tells us that most of the mass of QSO1 is concentrated in the black hole at the center,” Ignas Juodzbalis, a graduate student at the University of Cambridge and lead author of a study, said in a statement. “If the mass were more distributed, as there would be if there were a lot of stars, the gas would not have this perfect Keplerian rotation.”
Since Keplerian motion is governed by the laws of gravity, the team used velocity measurements of the surrounding gas to directly calculate the black hole’s mass. “This is an unprecedented result,” Maiolino said. “This is the first direct measurement of black hole mass within the first billion years after the Big Bang, and it is consistent with previous measurements.”
The results revealed that the black hole is not only supermassive, 50 million times the mass of the Sun, but it also makes up about two-thirds of QSO1’s total mass. Supermassive black holes typically make up only a small fraction of the total mass of their host galaxies. The discovery revealed that the ratio between the supermassive black hole and its galaxy is thousands of times greater than that of nearby galaxies.
The findings suggest that this black hole was born as a big boy, rather than forming from a collapsing star and relying on the gas surrounding it to grow to its massive size. The chemical composition of QSO1 also revealed that it is composed almost entirely of hydrogen and helium, with very little of heavier elements like oxygen found in a galaxy typically rich in stars and stellar debris.
“It seems that we have found a black hole that has no large host galaxy and that already has stellar processes,” Juodzbalis said. “This is very exciting because it is evidence of primordial black holes or direct collapse black holes, which have been theorized but not confirmed.”
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