Astronomers from the University of Hawaii's Institute for Astronomy (IfA) have discovered the most energetic type of cosmic explosion ever detected, dubbed "extreme nuclear transients" (ENT).
The extraordinary phenomenon occurs when massive stars – at least three times the mass of our Sun – are torn apart after getting too close to a supermassive black hole, releasing huge amounts of energy that can be seen from enormous distances. Scientists call it “the biggest series of explosions since the Big Bang.”
These ENT bursts are markedly different from any tidal disruption events (when stars are ripped apart by black holes) that have been observed, according to research published in the journal Science Advances.
They are nearly 10 times brighter and maintain this brightness for many years, far exceeding the total energy emitted by even the brightest supernova explosions.
The most energetic ENT studied, called Gaia18cdj, released 25 times more energy than the most powerful supernova ever known. While a typical supernova releases the equivalent of the Sun's entire 10-billion-year lifetime in just one year, ENTs release the energy of 100 Suns in the same time period.
The team, led by Jason Hinkle, discovered the ENTs while systematically searching for long-lasting bursts of light extending from the centers of galaxies in publicly available data, notably from the European Space Agency's Gaia mission.
These events show a gradual increase in brightness over a long period of time, unlike any known transient astronomical phenomenon. Data from several telescopes, including the University of Hawaii’s Asteroid Last Alert System (ATLAS) and the W.M. Keck Observatory, have confirmed their unique nature.
The enormous energies and smooth, elongated light curves of the ENTs suggest that they are not supernovae. Instead, the mechanism identified is the slow accretion of matter from a collapsed star onto a supermassive black hole.
The discovery provides a valuable new tool for studying supermassive black holes in distant galaxies. Because of their extreme brightness, scientists can observe ENTs from vast cosmic distances, which means looking back in time.
This opens up opportunities to learn about the growth of black holes when the universe was about half its current age, a time when galaxies were much more active than today.
Although 10 million times rarer than supernovae, future observatories such as NASA's Vera C. Rubin Observatory and Roman Space Telescope are expected to detect many more ENTs, contributing to our understanding of black hole activity in the early universe./.
Source: https://www.vietnamplus.vn/ngoai-bien-hat-nhan-cuc-do-vu-no-lon-nhat-vu-tru-ke-tu-big-bang-post1042487.vnp
Comment (0)