Researchers from Imperial London College (United Kingdom) have led a team that has observed thebrightest quasar discovered so far: U LAS J1120 + 064. The study, published inNature, could be useful to understand the formation of the universe since observations of these astronomical formations reveal the state of ionization of the intergalactic medium that took place one billion years after the Big Bang. Among the objects that are bright enough to be studied in detail, this is the most distant.
Quasars arevery luminous distant galaxies, powered by a supermassive black hole at their center. Their brightness makes them powerful beacons that can help investigate the time when the first stars and galaxies formed.
Quasars have historically been identified in optical studies, insensitive to redshift sources beyond 6.5. Now the work reveals thatULAS J1120 + 0641It is zoomed in at 7.085, which is 770 million years after the origin of the universe. The quasar closest to this point observed so far had a displacement of 6.44 (100 million years younger than the one located now). Studying the distance between the two “beacons” will serve to shed some light on a time about which scientists do not have much information.
“We think there are only about 100 bright quasars with a redshift greater than 7 in the entire sky,” explains Daniel Mortlock, lead author of the study and researcher at Imperial London College (UK). “Finding this object involved a painstaking search, but it was worth the effort to unravel some of the mysteries of the early Universe,” he adds. Similar objects that are more distant cannot be detected by tracking in visible light because their light, stretched by the expansion of the universe, has shifted almost completely into the infrared part of the spectrum by the time it reached Earth.
? This quasar is a vital evidence of the primordial universe ?, explains Stephen Warren, co-author of the work. “It is a very rare object that will help us understand how supermassive black holes grew a few hundred million years after the Big Bang,” he adds. Observations showed that lThe mass of the black hole at the center of ULAS J1120 + 0641 is equal to two billion times the mass of the Sun. Such a large mass is difficult to explain at such an early stage after the Big Bang. Current theories about the growth of supermassive black holes predict a slow increase in mass as the compact object draws matter from its surroundings.
