The James Webb Space Telescope (JWST) has been providing astronomers with groundbreaking insights into the early universe since its launch two years ago. With its ability to see back in time, thanks to its large mirrors and sensitivity to infrared light, the JWST has revealed that the early universe is even stranger than previously thought. Not only are early galaxies taking on unexpected shapes, but recent research has shown that black holes in the early universe are much larger than anticipated.
A team of researchers from the Center for Astrophysics | Harvard & Smithsonian, led by Fabio Pacucci, has found that the correlation between the mass of black holes and the properties of their host galaxies breaks down in the early universe. In the local universe, there is a supermassive black hole at the center of every massive galaxy, and there are tight correlations between the mass of the black hole and the galaxy. However, in the early universe, black holes are 10 to 100 times larger relative to the mass of their host galaxies.
Pacucci’s study, published in The Astrophysical Journal Letters, analyzed high-redshift galaxies observed by the JWST between 700 million and 1.5 billion years after the Big Bang. The data clearly showed that every supermassive black hole studied was over-massive compared to the stellar mass of its galaxy. This trend was consistent across multiple checks on the data, indicating that it was not an observational bias.
The question then arises: why are black holes in the early universe so big? Pacucci suggests that it may be due to a process called heavy seeding. In the early universe, gas clouds could have collapsed directly into black holes, bypassing the formation of stars. These black holes, known as heavy seeds, could have been 10,000 times the mass of the Sun or more. The presence of such massive black holes would have made star formation difficult or impossible due to the injection of a significant amount of energy into the system. It is likely that it took another 2 to 3 billion years after the Big Bang for the material outside the black holes to contribute a larger bulk of the galaxy’s mass.
Further research is needed to understand the steps between heavy seeds and more massive galaxies, as well as to confirm if these findings are representative of the early universe. Pacucci and his team are also investigating the consequences of heavy seeding for black hole formation in the high-redshift universe.
The discoveries made by the JWST are reshaping our understanding of the early universe. The telescope’s ability to peer back in time and observe distant galaxies has revealed unexpected phenomena, such as galaxies taking on unusual shapes and black holes being much larger than anticipated. As astronomers continue to analyze the data collected by the JWST, we can expect more surprises and a deeper understanding of the mysteries of the cosmos.
