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MIT astronomers have observed the starlight around some of the earliest quasars in the universe. The distant signals, which go back more than 13 billion years to the infancy of the universe, reveal clues about how the first black holes and galaxies developed. Quasars are dynamic centers of active galaxies, holding an unstable black hole at their core.
Most galaxies have a central black hole that periodically feeds on gas and stellar debris, producing short bursts of light in the form of a glowing ring as material move towards the black hole. On the other hand, Quasars can consume a lot of material over a much longer period of time, creating an extremely bright and long-lasting ring – so bright, in fact, that quasars are among the brightest objects in the universe. Because they are so bright, quasars outshine the rest of the galaxy in which they reside. But the MIT team was able to see for the first time the much fainter light from stars in the host galaxies of three old quasars. Based on this incredible light, the researchers estimated the size of each host galaxy relative to the size of the central black hole. They found that the black holes at the center of these quasars were much larger than those in their host galaxy, compared to their new counterparts.
The findings, published today in The Astrophysical Journal, could shed light on how the earliest supermassive black holes became so massive despite the relatively short cosmic time in which they could they grow. In particular, these earliest supermassive black holes may have emerged from a larger “seed” than modern black holes. “After the universe was formed, there were black holes that ate material and grew in a short period of time,” says study author Minghao Yue, a postdoc at the Kavli Institute for Astrophysics and Space Research. at MIT. “One of the big questions is understanding how these supermassive black holes got so big so quickly.”
“These black holes are millions of times more massive than the Sun, at a time when the universe is still in its infancy,” said study author Anna-Christina Eilers, professor of physics at MIT. – our findings imply that supermassive black holes in the early Universe may have gained mass before their host galaxy, and that the original seed of black holes may have been larger than they are today. today.” Eilers and Yue’s co-authors include MIT Kavli director Robert Simcoe, MIT Hubble Fellow and postdoc Rohan Naidu, and colleagues in Switzerland, Austria, Japan and North Carolina State University.
Great woods
The sheer brightness of quasars has been evident since astronomers first discovered the objects in the 1960s. They then assumed that the quasar’s light came from a single “point source” similar to a star. Scientists called the objects “quasars,” short for “quasi-stellar” object. Since these first observations, scientists have discovered that quasars are not really a strong source, but rather come from the clustering of supercharged and persistent black holes at the centers of galaxies in the there are also stars, which are much fainter compared to their brilliant cores. .
Separating the light from the black hole at the center of a quasar from the light from the stars of the host galaxy is a major challenge. It’s a bit like distinguishing a field of fireflies around a medium-sized searchlight. But in recent years, astronomers have had many more opportunities to do this thanks to the launch of NASA’s James Webb Space Telescope (JWST), which you can see further back in time, and with much higher sensitivity and resolution than any observatory currently in existence. In their new study, Yue and Eilers used a special period at JWST to observe six known ancient quasars, periodically from the fall of 2022 until next spring. In total, the team collected more than 120 hours of observations of the six distant objects.
“The quasar dwarfs its host galaxy by orders of magnitude. And previous images were not sharp enough to distinguish what the host galaxy and its stars are like.” all similar,” Yue says. “Now, for the first time, we can reveal the light from these stars by carefully modeling the much sharper images of these quasars from JWST.”
Light balance
The team compiled the imaging data that JWST had collected from each of the six distant quasars, which they estimate are about 13 billion years old. That data includes measurements of the light from each quasar at different wavelengths. The researchers fed that data into a model to determine how much of that light is likely to come from a “point source,” such as a central black hole’s accretion disk, versus a more distant source. diffuse, such as light from the surrounding environment. , scattered stars of the host system.
Through this modeling, the team split the light from each quasar into two components: light from the luminous disk of the central black hole and light from the more diffuse stars of the host galaxy. The amount of light from both sources is a reflection of their total mass. The researchers estimate that, for these quasars, the ratio between the mass of the central black hole and the mass of the host galaxy was about 1:10. This, they realized, was in stark contrast to the current mass balance of 1:1,000, in which recently formed black holes are much smaller than their host galaxy.
“This tells us something about what grows first: Does the black hole grow first, and the galaxy catches up next? Or does the galaxy and its stars grow first, influencing and controlling the growth of the black hole?” Eilers explains. “We see that black holes appear to be growing faster in the early universe than their host galaxy. This is preliminary evidence that the original seed of black holes may have been more massive then.” “There must have been some way by which a black hole gained mass before its host galaxy in those first billions of years,” Yue said. “This is the first evidence we’ve seen for this, which is exciting.”
Source: Phys.org
2024-05-08 09:25:26
#Astronomers #track #invisible #light #ancient #quasars #Spacepage
