How supermassive black holes, which have masses billions of times that of our Sun, formed so rapidly—less than a billion years after the Big Bang—is clarified by a recent study published in Astronomy & Astrophysics.
The study, which was carried out by scientists from the National Institute for Astrophysics (INAF), examined 21 of the most distant quasars ever found. The Chandra and XMM-Newton space telescopes were used to observe these quasars at X-ray wavelengths.
The results provide a convincing explanation for the immense masses of these quasars in the early Universe by indicating that the supermassive black holes at their centers, which were generated during the Universe’s “cosmic dawn,” most likely expanded through incredibly fast and furious accretion.
Supermassive black holes, sometimes referred to as active galactic nuclei, are the driving force behind quasars, which are extremely bright active galaxies. Quasars are among the brightest and most distant objects in the universe because of the enormous quantities of energy that these black holes release when they draw in matter. The quasars examined in this study are among the oldest cosmic structures yet seen, having formed when the Universe was less than a billion years old.
X-ray Perspectives on the Accretion of Black Holes
An altogether unexpected behavior of the supermassive black holes at their centers was discovered in this work through the examination of X-ray emissions from these objects: a relationship between the form of the X-ray emission and the velocity of the winds of matter spewed by the quasars was discovered. The temperature of the gas in the corona, the area that releases X-rays nearest to the black hole, is correlated with wind speed, which can reach thousands of kilometers per second. Therefore, it was discovered that the corona was linked to the black hole’s strong accretion processes.
Faster winds are seen in quasars with low-energy X-ray emission, which indicates a lower coronal temperature. This suggests a very fast growth phase that surpasses the Eddington limit, a physical limit for matter accretion, hence the term “super-Eddington.” On the other hand, slower winds are typically seen in quasars that emit higher-energy X-rays.
“Our work suggests that the supermassive black holes at the center of the first quasars formed within the first billion years of the Universe’s life may have actually increased their mass very rapidly, challenging the limits of physics,” says Alessia Tortosa, lead author of the study and researcher at INAF in Rome. “The discovery of this connection between X-ray emission and winds is crucial for understanding how such large black holes could have formed in such a short time, thus providing a concrete clue to solve one of the greatest mysteries of modern astrophysics.”
Campaigns for Observation and the HYPERION Project
The European Space Agency’s (ESA) XMM-Newton space telescope, which made it possible to observe the quasars for about 700 hours, was primarily responsible for the outcome. The majority of the data was gathered as part of the Multi-Year XMM-Newton Heritage Programme between 2021 and 2023. The HYPERION project, led by Luca Zappacosta, a researcher at INAF in Rome, aims to examine hyperluminous quasars during the cosmic start of the Universe. A group of Italian scientists oversaw the massive observation effort, which was made possible by INAF, the program’s funding source. This allowed for the advancement of cutting-edge studies on the evolutionary dynamics of the Universe’s early structures.
“In the HYPERION program, we focused on two key factors: on the one hand, the careful selection of quasars to observe, choosing the titans, meaning those that had accumulated as much mass as possible, and on the other hand, the in-depth study of their properties in X-rays, something never attempted before on such a large number of objects from the cosmic dawn,” says Luca Zappacosta, a researcher at INAF in Rome. We hit the jackpot! The results we’re getting are genuinely unexpected, and they all point to a super-Eddington growth mechanism of the black holes.”
Implications for X-ray Astronomy in the Future
Future X-ray missions like ATHENA (ESA), AXIS, and Lynx (NASA), which are slated to launch between 2030 and 2040, would benefit greatly from the insights this study offers. Actually, the outcomes will be helpful for refi
