Astronomers have discovered the brightest known galaxy that existed during the so-called cosmic noon, a period roughly 3 billion years after the Big Bang. This stage in the history of the universe was marked by intense star formation and the rapid growth of black holes that absorbed matter at an unprecedented rate. About this informs Phys.
At this time, so-called “small red dots” (LRDs) were already known – bright objects in the early universe that emitted red light. As it turned out, this glow comes from the active cores of galaxies, where supermassive black holes with masses millions of times greater than the Sun are located at the center. They absorb matter so quickly that they illuminate the space around them, while hiding the light from the stars in their galaxies.
Thanks to the James Webb Space Telescope, astronomers have found an object that stands out even among LRDs—a galaxy nicknamed the Great Red Dot (BiRD). Despite the fact that its size is not larger than other LRDs, it is significantly brighter than several hundred analogues that scientists have previously discovered.
BiRD exhibits a number of unique properties. In particular, it ejects helium at a speed of 830 km/s, which partially blocks the expected light. Despite the activity of LRD in the X-ray and radio ranges, BiRD does not detect such activity. Scientists speculate that the X-ray radiation may be blocked by a thick cloud of gas around the core, or the central black hole absorbs matter so intensely that it forms a disc that blocks the radiation. The reasons for the absence of radio waves currently remain unclear.
Interestingly, BiRD is similar to two other LRD galaxies discovered in the same period—they also eject helium and are similar in size. This allows scientists to assume that such objects could be typical for this stage of the universe’s development. Astronomers hope to find more such objects, because they allow us to better understand what the universe was like in its “youth” and trace the evolution of supermassive black holes at the center of galaxies.
