LRDs were first detected in 2022 when NASA's James Webb Space Telescope (JWST) became fully operational.
The most recent study was published on the 24th (local time) in the international journal Nature Astronomy by an international research team led by China's Wuhan University and Hunan Normal University.
The research team interpreted this light as likely originating from a star-forming host galaxy.
The structure appears to be a black hole at the center of the LRD surrounded by a small galaxy.
LRDs have become a very important research subject for understanding how black holes and galaxies grew together in the early universe."
The astronomical community is deepening its debate over the identity of "little red dots" (LRDs), unidentified celestial objects primarily found in the early universe hundreds of millions of years after the Big Bang 13.8 billion years ago. Recent studies published in international journals have lent weight to the possibility that LRDs are black holes growing while shrouded in thick gas, while also presenting observational evidence that small star-forming galaxies exist around them.
LRDs were first detected in 2022 when NASA's James Webb Space Telescope (JWST) became fully operational. The telescope began observing extremely distant objects from the early universe that had been largely invisible to the Hubble Space Telescope. Because LRDs are very small and bright at their centers, appearing almost as points in observational images, two competing hypotheses have emerged: that they are either "very small, dense galaxies" or "massive black holes."
The most recent study was published on the 24th (local time) in the international journal Nature Astronomy by an international research team led by China's Wuhan University and Hunan Normal University. The team stacked and averaged 217 LRD images to precisely observe light from outside the centers that was too faint to distinguish in individual images. The result revealed ring-shaped light in the periphery that cannot be explained by a single central object alone.
The research team interpreted this light as likely originating from a star-forming host galaxy. The structure appears to be a black hole at the center of the LRD surrounded by a small galaxy. The average size of the galaxy surrounding the LRD, as estimated from observations, is approximately 210 parsecs (pc) in radius. One parsec is equivalent to about 3.26 light-years.
Woong-Seob Jeong, a principal researcher at the Korea Astronomy and Space Science Institute, said, "They found peripheral light that was not readily visible in individual LRDs," adding, "Compared to our Milky Way, which spans tens of thousands of parsecs, the galaxy surrounding the LRD is extremely small." He continued, "Researchers were initially quite surprised. LRDs have become a very important research subject for understanding how black holes and galaxies grew together in the early universe."
Another key study on the identity of LRDs was published on the 12th in the international journal Nature. A research team led by Rohan Naidu, a researcher at MIT's Kavli Institute for Astrophysics and Space Research, analyzed one LRD called "MoM-BH*-1" and concluded that it is a black hole surrounded by thick gas.
