Researchers investigated three mysterious objects in the early universe. Shown here are their color images, composed of three NIRCam filter bands aboard the James Webb Space Telescope. They are extremely compact at red wavelengths (giving them the term “small red dots”), with some evidence for spatial structure at blue wavelengths. Credit: Bingjie Wang/Penn State
NASAS ‘ The James Webb Space Telescope has discovered mysterious objects in the early universe that challenge current galaxy and supermassive theories black hole evolution.
These objects contain old stars and massive black holes, much larger than expected, suggesting a rapid and unconventional form of early galaxy formation. The findings highlight significant inconsistencies with existing models, and the objects’ unique properties indicate a complex early cosmic history.
Advanced Discovery in the Early Universe
A recent discovery by NASA’s James Webb Space Telescope (JWST) confirmed that bright, very red objects previously discovered in the early universe challenge ideas about the origin and evolution of galaxies and their supermassive black holes. .
Led by researchers from Penn State and using the NIRSpec instrument on JWST as part of the RUBIES survey, the international team identified three enigmatic objects dating back 600-800 million years Big Bang, a time when the universe was only 5% of its current age. They announced the discovery on June 27 in the journal Astrophysical Journal Letters.
The scientists analyzed spectral measurements, or the intensity of different wavelengths of light emitted by the objects. Their analysis found signatures of “old” stars, hundreds of millions of years old, much older than expected in a young universe.
The James Webb Space Telescope (JWST) provides a window into the distant past of the cosmos, capturing images of the universe’s first galaxies and stars that formed over 13.5 billion years ago. Credit: NASA-GSFC, Adriana M. Gutierrez (CI Lab)
Unexpected Findings in Galactic Evolution
The researchers said they were also surprised to discover the signatures of large supermassive black holes in the same objects, estimating that they are 100 to 1,000 times more massive than our own supermassive black hole. Milky Way. Neither of these is expected in current models of galaxy growth and supermassive black hole formation, which expect galaxies and their black holes to grow together over billions of years of cosmic history.
“We have confirmed that these appear to be filled with ancient stars – hundreds of millions of years old – in a universe that is only 600-800 million years old. Surprisingly, these objects hold the record for the earliest signatures of old starlight,” said Bingjie Wang, a postdoctoral researcher at Penn State and lead author of the paper. “It was completely unexpected to find old stars in a very old universe. ri. Standard models of cosmology and galaxy formation have been remarkably successful, however, these bright objects do not fit well into those theories.”
Researchers first discovered the massive objects in July 2022, when initial data was released by JWST. The team published a paper in Nature a few months later announcing the existence of the facilities.
Challenges in space observation
At the time, researchers suspected the objects were galaxies, but followed up their analysis by taking spectra to better understand the objects’ true distances, as well as the sources powering their immense light.
The researchers then used the new data to draw a clearer picture of what the galaxies looked like and what was inside them. Not only did the team confirm that the objects were indeed galaxies near the beginning of time, but they also found evidence of surprisingly large supermassive black holes and a surprisingly old population of stars.
“It’s very confusing,” said Joel Leja, assistant professor of astronomy and astrophysics at Penn State and co-author on both papers. “You can make this fit uncomfortably into our current model of the universe, but only if we conjure up an exotic, extremely fast formation at the beginning of time. This is, without a doubt, the most unique and interesting group of objects I have seen in my career.”
JWST is designed to observe the phenomena that occurred immediately after the Big Bang, using its advanced infrared capabilities to see through cosmic dust and detect hidden structures in space. Credit: Northrop Grumman
Mysteries of ancient galactic structures
JWST is equipped with instruments with infrared sensors capable of detecting light that has been emitted by the most ancient stars and galaxies. Essentially, the telescope allows scientists to look back in time roughly 13.5 billion years, near the beginning of the universe as we know it, Leja said.
One challenge to analyzing ancient light is that it can be difficult to distinguish between the types of objects that may have emitted the light. In the case of these early objects, they have clear characteristics of both supermassive black holes and old stars. However, Wang explained, it’s not yet clear how much of the observed light comes from each — meaning these could be early galaxies that are unexpectedly old and more massive than even our own Milky Way, forming much earlier than the models predict, or they could be more normal-mass galaxies with “supermassive” black holes, roughly 100 to 1000 times more massive than such a galaxy would be today.
“Distinguishing between light from material falling into a black hole and light emitted by stars in these small, distant objects is challenging,” Wang said. “This inability to show the difference in the current data set leaves ample room for interpretation of these intriguing artifacts. Honestly, it’s exciting to have so much of this mystery to figure out.”
In addition to their inexplicable mass and age, if some of the light is indeed from supermassive black holes, then they are also not normal supermassive black holes. They produce far more ultraviolet photons than expected, and similar objects studied with other instruments lack the hallmarks of supermassive black holes, such as hot dust and bright X-ray emission. But perhaps most surprising, the researchers said , is how massive they look.
“Normally, supermassive black holes pair up with galaxies,” Leja said. “They grow up together and go through all their major life experiences together. But here, we have a fully formed adult black hole living inside what must be a small galaxy. That doesn’t make sense, because these things should grow together, or so we thought.”
Researchers were also puzzled by the extremely small size of these systems, only a few hundred light-years across, roughly 1,000 times smaller than our own Milky Way. The stars are about as numerous as our own Milky Way galaxy—with somewhere between 10 billion and 1 trillion stars—but contained within a volume 1,000 times smaller than the Milky Way.
Leah explained that if you took the Milky Way and compressed it to the size of the galaxies they found, the nearest star would be almost in our own solar system. The supermassive black hole at the center of the Milky Way, about 26,000 light-years away, would be only about 26 light-years from Earth and visible in the sky as a giant pillar of light.
“These early galaxies would be so dense with stars—stars that must have formed in a way we’ve never seen before, under conditions we’d never expect over a period in which we’d never expect never see them,” Leja said. “And for whatever reason, the universe stopped creating objects like these after just a few billion years. They are unique to the early universe.”
The researchers hope to follow up with more observations, which they said could help explain some of the objects’ mysteries. They plan to obtain deeper spectra by pointing the telescope at the objects over long periods of time, which will help disentangle the emission from stars and potential supermassive black holes by identifying specific absorption signatures that would be present in each of them.
“There is another way we can have a breakthrough, and this is the right idea,” Leja said. “We have all these pieces of the puzzle and they only fit together if we ignore the fact that some of them are breaking. This problem lends itself to a stroke of genius that has so far eluded us, all of our collaborators, and the entire scientific community.”
Reference: “RUBIES: Evolved stellar populations with extended formation histories at z ~ 7–8 in massive candidate galaxies identified with JWST/NIRSpec” by Bingjie Wang, 冰洁 王, Joel Leja, Anna de Graaff, Andrea Webel B. , 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 and Christina C. Williams, 26 June 2024, The Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/ad55f7
Wang and Leja received funding from NASA’s general observer program. The research was also supported by the International Institute of Space Sciences in Bern. The work is based in part on observations made with the NASA/ESA/CSA James Webb Space Telescope. Computations for the research were performed on Penn State’s Institute for Computer and Data Science’s Roar supercomputer.
Other co-authors on the paper are Anna de Graaff of the Max-Planck-Institut für Astronomie in Germany; Gabriel Brammer of Dawn Space Center and Niels Bohr Institute; Andrea Weibel and Pascal Oesch from the University of Geneva; Nikko Cleri, Michaela Hirschmann, Pieter van Dokkum and Rohan Naidu of Yale University; Ivo Labbé from Stanford University; Jorryt Matthee and Jenny Greene of Princeton University; Ian McConachie and Rachel Bezanson from the University of Pittsburgh; Josephine Baggen of Texas A&M University; Katherine Suess of the Observatoire de Sauverny in Switzerland; David Setton of the Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research; Erica Nelson of the University of Colorado; Christina Williams of the US National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory and the University of Arizona.
