Astronomers observe elusive starlight around ancient quasar

This observation suggests that some of the early “monster” black holes grew from giant cosmic seeds. Astronomers at the Massachusetts Institute of Technology have observed elusive starlight around some of the universe’s earliest quasars. Distant signals dating back more than 13 billion years to the early days of the universe provide insightful clues about how the first black holes and galaxies evolved. Quasars are the glowing centers of active galaxies with greedy supermassive black holes at their centers. Most galaxies have a black hole at their center that occasionally preys on gas and stellar debris, producing short bursts of light in the form of glowing rings as material swirls toward the black hole. In contrast, quasars consume vast amounts of material over much longer periods of time, producing extremely bright and long-lived rings. So bright that quasars are actually among the brightest objects in the universe. Quasars are so bright that they outshine the rest of the galaxy in which they live. But for the first time, the MIT team was able to observe much weaker light from stars in the parent galaxies of three ancient quasars. Based on this elusive starlight, the researchers estimated the mass of each host galaxy by comparing it to the mass of the supermassive black hole at its center. They found that, compared to their modern-day counterparts, the central black holes of these quasars are much more massive than their host galaxies. The findings, published today in the Astrophysical Journal, could shed light on how the first supermassive black holes became so massive despite the relatively short growth time of the universe. There is sex. In particular, these early supermassive black holes may have formed from “seeds” that were larger than more modern black holes. “After the universe formed, there was a black seed hole that consumed matter and grew in a very short period of time,” said study author and postdoctoral fellow at the Kavli Institute for Astrophysics and Space Studies at the Massachusetts Institute of Technology. Minghao Yue said. “One of the big questions is understanding how these massive black holes are able to grow so large and so quickly.” “When the universe is still in its infancy, these black holes are billions of times more massive than the sun,” says study author Anna Christina Eilers, an assistant professor of physics at MIT. “Our findings suggest that supermassive black holes in the early universe gained mass before their parent galaxies, and that the original black hole seeds may have been more massive than they are today. ” Eilers and Yue’s co-authors include her MIT Kavli Director Robert Simcoe, her MIT Hubble Fellow and postdoc Rohan Naidu, and collaborators in Switzerland, Austria, Japan, and North Carolina State University. .

The light from each quasar is separated into two components. Light from the central black hole’s luminescent disk and light from the more diffuse stars of the parent galaxy. The amount of light from both sources reflects their combined mass. The researchers estimate that in these quasars, the ratio of the mass of the central black hole to the mass of the host galaxy is about 1:10. They found that this is in stark contrast to today’s 1:1,000 mass balance, where the mass of the new black hole is much less than that of its parent galaxy. “This tells us something about what grows first. Will black holes grow first, and then galaxies catch up?” Or will the galaxy and its stars grow first, dominating and controlling the growth of the black hole? ” Eilers explains. “We found that black holes in the early universe appeared to be growing faster than their parent galaxies, a preliminary indication that the original black hole seeds may have been larger at the time. It’s proof.” “During the first billion years, there must have been some mechanism by which the black hole gained mass faster than its parent galaxy,” Yue added. “This is kind of the first evidence we’ve seen of it, so we’re very excited.”

source: https://iopscience.iop.org/article/10.3847/1538-4357/ad3914