An international team of astronomers has made a groundbreaking discovery thanks to the James Webb Space Telescope (JWST): an ancient “dormant” supermassive black hole located in a galaxy seen as it was nearly 13 billion years ago. This result was published in the prestigious journal Nature and represents a milestone in modern astrophysics. Also involved were Italian experts from the National Institute of Astrophysics (INAF), the Scuola Normale Superiore of Pisa and the Sapienza University of Rome
The black hole, with a mass equal to 400 million times that of the Sun, it dates back less than 800 million years after the Big Bangmaking it one of the oldest and most massive objects ever detected. AND the first non-active supermassive black hole observed during the epoch of reionization, a critical period of the early universe in which intergalactic gas was ionized by the first stars and galaxies.
The discovery of such an old and inactive supermassive black hole raises new questions about the growth mechanisms of black holes and their influence on host galaxies. The mass ratio between the black hole and its host galaxy, in this case 40% of the total stellar mass, suggests a phase of extremely rapid growth followed by a long period of inactivity. This imbalance has important implications for understanding star formation and galactic evolution.
“If growth occurred at a rate below the Eddington limit, the black hole would have to grow gas continuously over time to hope to reach the observed mass. It would therefore be very unlikely to observe it in a dormant phase“, explains Raffaella Schneider, professor of the Department of Physics at Sapienza University.
False-color image obtained by the JWST space telescope, showing a small fraction of the GOODS-North field. The galaxy highlighted in the box hosts an ancient ‘dormant’ supermassive black hole. Credit: JADES Collaboration
The discovery was made possible thanks to the sensitivity and resolution capacity of the JWSTwhich allows us to observe previously inaccessible details about the most distant and dim cosmic objects. The telescope, a collaboration between NASA, ESA (European Space Agency) and CSA (Canadian Space Agency), is currently the most advanced instrument for infrared astronomy.
With JWST, astronomers hope to identify other dormant black holes in the early universe, offering a new window into the early stages of the growth of supermassive black holes and their impact on early galaxies. This research could solve some of astrophysics’ most persistent mysteries, such as the rapid formation of giant black holes shortly after the Big Bang.
Alessandro Trinca, post-doc researcher currently working at the University of Insubria but already post-doc at INAF in Rome for a year, explains: “This imbalance suggests that the black hole had a very rapid growth phase, subtracting gas from the galaxy’s star formation. It stole all the gas it had available before becoming dormant, leaving the stellar component high and dry“;.
Rosa Valiante, researcher at INAF in Rome involved in the international team and co-author of the article, adds: “Understanding the nature of black holes has always been a topic that fascinates the collective imagination: they are apparently mysterious objects that put ‘famous’ scientific theories such as those of Einstein and Hawking to the test. The need to observe and understand black holes, from when they form to when they become as massive as billions of times our Sun, pushes not only scientific research to progress, but also technological advancement”.
Cover image. Artistic illustration representing the potential appearance of the supermassive black hole discovered by the research team during its phase of intense super-Eddington activity. Credit: Jiarong Gu
