National Aeronautics and Space Administration (NASA)of James Webb Space Telescope A mysterious object from the early universe has been discovered that calls into question current theories about galaxies and supermassive stars. Black Hole evolution.
These objects contain much larger, older stars and massive black holes than expected, suggesting rapid and unconventional forms of early galaxy formation. The discoveries highlight major inconsistencies with existing models, and the objects’ unique properties suggest a complex early cosmic history.
Groundbreaking discoveries in the early universe
A recent discovery by NASA’s James Webb Space Telescope (JWST) has confirmed that a very red, luminous object previously detected in the early universe challenges existing ideas about the origin and evolution of galaxies and supermassive black holes.
As part of the RUBIES survey, an international team led by researchers from Pennsylvania State University used JWST’s NIRSpec instrument to identify three mysterious objects dating back 600 to 800 million years after Earth’s formation. big bangAt the time, the universe was only 5% of its current age. They published their findings on June 27 in the journal Nature. Astrophysical Journal Letters.
Scientists used spectroscopy — analyzing the intensity of different wavelengths of light emitted by the object — to discover the signatures of “old” stars that are hundreds of millions of years old, far older than would be expected in a young universe.
Unexpected discovery in galactic evolution
The researchers said they were also surprised to find the signature of a huge supermassive black hole in the same celestial body, which they estimate to have a mass between 100 and 1,000 times that of Earth’s supermassive black hole. milky wayNeither of these two phenomena is predicted by current models of galaxy growth and the formation of supermassive black holes, which expect galaxies and black holes to grow together over billions of years of cosmic history.
“We found that these objects are packed with stars that are hundreds of millions of years old, even though the universe is only 600 to 800 million years old. Remarkably, these objects preserve the oldest traces of old starlight,” said Bingjie Wang, a postdoctoral researcher at Penn State and lead author of the paper. “We were completely unexpected to find old stars in such a young universe. The standard models of cosmology and galaxy formation have been incredibly successful, but these luminous objects do not quite fit those theories.”
Researchers first discovered the massive object in July 2022, when the first data set from JWST was released. The team published a paper on the object in November 2020. Nature A few months later, the object’s existence was announced.
Space Observation Challenges
At the time, researchers suspected the object was a galaxy, but continued to take and analyze spectra to better understand the object’s actual distance and the source of its enormous light.
The researchers then used the new data to paint a clearer picture of what the galaxies look like and what they’re like inside. Not only did the team confirm that these objects are indeed ancient galaxies, but they also found evidence of surprisingly large supermassive black holes and surprisingly ancient clusters of stars.
“It’s very confusing,” says Joel Reja, an assistant professor of astronomy and astrophysics at Penn State and a co-author on both papers. “You can force this into our current models of the universe, but only if you assume there was some exotic, unusually rapid formation at the beginning of time. This is without a doubt the most bizarre and interesting collection of objects I’ve seen in my career.”
Mystery of the ancient galactic structure
JWST is equipped with infrared-sensing instruments that can detect light emitted by the oldest stars and galaxies. Essentially, the telescope will allow scientists to look back in time, about 13.5 billion years ago, near the beginning of the universe as we know it, Reja said.
One challenge in analyzing ancient light is that it can be hard to distinguish between the types of objects that may have emitted it. In the case of these early objects, the signatures of both supermassive black holes and old stars are clearly evident. But it’s not yet clear how much of the observed light comes from each, Wang explains. That means they could be early galaxies that are unexpectedly older and even more massive than our own Milky Way, forming much earlier than models predict. Or they could be more conventional galaxies with “supermassive” black holes, roughly 100 to 1,000 times more mass than our current galaxy.
“It’s hard to distinguish between the light from matter falling into a black hole and the light emanating from these tiny, distant stars,” Wang said. “Current data sets don’t tell us the difference, so there’s plenty of room for interpretation of these fascinating objects. And frankly, it’s exciting that there are so many mysteries still to be uncovered.”
Unexplained mass and age aside, if some of the light is indeed from supermassive black holes, they’re not ordinary supermassive black holes: They emit far more ultraviolet photons than expected, and similar objects studied with other instruments don’t show the hallmarks of supermassive black holes, such as hot dust and bright X-ray emission. But the researchers said what’s perhaps most surprising is just how massive they are.
“Usually supermassive black holes are paired with galaxies,” Reja said, “and they grow together and go through all of the major experiences of life together. But here we have a fully formed, adult black hole sitting in what should be a baby galaxy. This doesn’t make much sense, because these are supposed to grow together, or at least that’s what we thought.”
Researchers were also perplexed by the incredibly tiny size of these systems: just a few hundred light-years in diameter, roughly one-thousandth the size of our own Milky Way galaxy. These systems have roughly the same number of stars as our own Milky Way galaxy, between 10 billion and one trillion stars, but their volume is only one-thousandth the size of the Milky Way.
Reja explained that if the Milky Way were compressed to the size of the galaxy they found, the nearest star would be roughly within our solar system. The supermassive black hole at the center of the Milky Way is about 26,000 light-years away, but only 26 light-years from Earth, and is visible in the sky as a giant pillar of light.
“These early galaxies must have been incredibly dense with stars. These stars must have formed in ways we’ve never seen, under conditions we’ll never see, at times we’ll never see,” Reja says. “And for some reason, the universe stopped making these objects after just a few billion years. These are unique to the early universe.”
The researchers hope to continue with further observations, which they say may help unlock some of the objects’ mysteries. They plan to aim the telescope at the objects for longer periods of time to take deeper spectra. This will help them distinguish between stellar radiation and potential supermassive black holes by identifying the specific absorption signatures present in each object.
“There’s a different way to make a breakthrough, and that’s exactly the right idea,” Reja says. “We have all the pieces of the puzzle, but in order for them to fit together, we need to ignore the fact that some of them are broken. This problem could be solved with a stroke of genius that has eluded us, all our collaborators, and the scientific community at large until now.”
Reference: “RUBIES: An evolved stellar population with an extended formation history at z ∼ 7–8 in candidate massive galaxies identified by JWST/NIRSpec”, Bingjie Wang, Bingjie Wang, Joel Leja, Anna de Graaff, Gabriel B. Brammer, Andrea Weibel, Pieter van Dokkum, Josephine FW Baggen, Katherine A. Suess, Jenny E. Greene, Rachel Bezanson, Nikko J. Cleri, Michaela Hirschmann, Ivo Labbé, Jorryt Matthee, Ian McConachie, Rohan P. Naidu, Erica Nelson, Pascal A. Oesch, David J. Setton, Christina C. Williams, 26 June 2024, Astrophysical Journal Letters.
Posted on: 10.3847/2041-8213/ad55f7
Wang and Reja received funding from NASA’s General Observations Program. The research was also supported by the International Space Science Institute in Bern. The research is based in part on observations from the NASA/ESA/CSA James Webb Space Telescope. Computations for this study were performed on the Roar supercomputer at Pennsylvania State University’s Computational and Data Science Institute.
Other co-authors on the paper are Anna de Graaff of the Max Planck Institute for Astronomy in Germany, Gabriel Brammer of the Cosmic Dawn Centre and Niels Bohr Institute, Andrea Weibel and Pascal Oesch of the University of Geneva, Nico Cleri, Michaela Hirschmann, Pieter van Dokkum and Rohan Naidu of Germany. Yale University; Ivo Rabé of Stanford University; Jorrit Massey and Jenny Green Princeton UniversityThe researchers include Ian McConachie and Rachel Bezanson of the University of Pittsburgh, Josephine Baggen of Texas A&M University, Katherine Suess of the Sauvegin Observatory in Switzerland, David Seton of the Kavli Institute for Astrophysics and Space Sciences at the Massachusetts Institute of Technology, Erica Nelson of the University of Colorado, and Christina Williams of the National Science Foundation’s National Laboratory for Optical and Infrared Astronomy and the University of Arizona.