This pair of images represents an extraordinarily large survey of galaxies studying the growth of supermassive black holes over billions of years. The main goal of the study, as reported in our latest press release, was to explain why astronomers see a major slowdown in how rapidly supermassive black holes (those with millions to billions times the mass of the Sun) grow today compared to about ten billion years ago when growth of these black holes was at its peak.
The galaxies in the centers of these two panels each contain a supermassive black hole that is representative of this change in the consumption rate of material. The Chandra source in the spiral galaxy on the left is named 2CXO J033225.7-274936, and it is located about 5.6 billion light-years from Earth. This galaxy glows strongly in X-rays detected by NASA’s Chandra X-ray Observatory because gas rapidly falling into a supermassive black hole is heated up and produces large amounts of radiation including X-rays. In this image, X-rays from Chandra (purple) have been combined with optical data from NASA’s Hubble Space Telescope (blue) and infrared data from NASA’s James Webb Space Telescope (red and green).
The panel on the right shows an elliptical galaxy that is significantly closer to Earth at a distance of about 3 billion light-years. The X-ray source detected by Chandra (purple) is named 2CXO J033215.3-275044 and is much fainter than the other source, indicating that the supermassive black hole is consuming material at a much slower rate. Its growth rate is only about 3% of that for the black hole on the left, reflecting the average decrease with time seen in the new study. Once again, the X-rays from Chandra are shown in a composite image with Hubble’s optical data and Webb’s infrared data.
To address the question of why supermassive black hole growth has slowed, the team used a combination of surveys ranging from shallow surveys of large regions of the sky to extremely long studies of small fields. The new study combined data from Chandra, ESA’s XMM-Newton, and eROSITA of about 1.3 million galaxies and 8,000 growing supermassive black holes in a “wedding cake” design observations. XMM-Newton and eROSITA provided the middle and bottom tiers with wider but shallower observations. Meanwhile, Chandra contributed the top tier with deep observations covering a relatively small area that allowed the detection of fainter and more distant growing black holes.
The scientists ran tests of the three main possible scenarios currently being considered for the slowdown of black hole growth. These options — included in an explanatory graphic — are: could the decline in black hole growth be caused by less efficient rates of consumption (top panel), or by smaller typical black hole masses, (middle panel) or by fewer actively growing black holes (bottom panel)?
Their analysis of the data led them to the conclusion that black holes are indeed consuming material less rapidly the later they are found after the big bang, as visualized in the top panel. The researchers expect this trend of slower-growing black holes to continue into the future.
A paper describing these results appeared in The Astrophysical Journal in December 2025. The authors of the paper were Zhibo Yu (Penn State University), Niel Brandt (Penn State), Fan Zou (University of Michigan), Bin Luo (Nanjing University, China), Qingling Ni (Max Planck Institute for Extraterrestrial Physics, Germany), Don Schneider (Penn State), and Fabio Vito (Italian National Institute for Astrophysics).
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
This release features two composite images, presented side-by-side for ease of comparison. Each image represents an extraordinarily large survey of galaxies, with a single galaxy positioned at the center of each frame.
The two images appear visually similar. Both feature dozens of galaxies; glowing specks and elliptical shapes in purples, golden oranges, blues, and whites, scattered across the blackness of space. In both images, blue colors represent optical data from Hubble. Reds and greens represent infrared data from Webb. And purples and pinks represent X-ray data from Chandra.
The focal points of this release are the galaxies at the center of each frame. Both galaxies glow in pinks and whites, and both have supermassive black holes at their core. But the featured galaxy on our left is far more distant than the featured galaxy on our right.
The galaxy in the image on our left is a spiral galaxy some 5.6 billion light-years from Earth. Here, it resembles a large dot with a hazy, neon pink outer ring, and a white core. The strong pink glow is due to gas rapidly falling into the supermassive black hole at its core. When that gas is heated up, it produces large amounts of radiation, including X-rays.
At the center of the image on our right is an elliptical galaxy that is significantly closer to Earth, at a distance of about 3 billion light-years. Here, this galaxy resembles an egg with an oval-shaped white outer ring, and a round pink circle at its core. This galaxy’s supermassive black hole is a much fainter source of X-rays than the previously mentioned source on our left. This indicates that the supermassive black hole on our right is consuming material at a much slower rate than the more distant supermassive black hole on our left.
|
|||||||||||||||||||||||||||
 |
|
|||||||||||||||||||||||||||
|
