The James Webb Space Telescope, operated by NASA in collaboration with European and Canadian space agencies, has identified a triple galaxy system named ‘The Stingray’, dating back to a time when the universe was only 1.1 billion years old.
This discovery provides valuable insights into the so-called ‘little red dots’ (LRDs), cosmic structures from the early universe that have intrigued astronomers since their first detection in 2023. Initially, LRDs were associated with galaxies hosting active black holes, known as active galactic nuclei (AGNs), but there are also hypotheses suggesting they could be ancient supermassive stars or exotic objects related to black holes.
According to the Live Science portal, a study published on March 9, 2026, in the journal Astronomy & Astrophysics details the analysis of the Stingray system.
Researchers have reconstructed the recent star formation history in this galactic ensemble, suggesting that interactions among the galaxies may have led an AGN to a peculiar state, akin to a transition phase to or from a red dot. The galaxy hosting this AGN was classified as a ‘transition red dot’ (tLRD), highlighting its relevance in understanding the evolution of these objects.
The Stingray system consists of three distinct galaxies. The first, a Balmer break galaxy, is relatively massive and exhibits more stable evolution. The second is the tLRD, which displays unique characteristics. The third is a smaller satellite galaxy with intense star formation, seemingly integrated into the system more recently.
Although observational limitations have prevented astronomers from precisely determining the origin of this galactic trio, they have developed a scenario based on indirect evidence obtained by the Canadian NIRISS Unbiased Cluster Survey, one of the deepest surveys conducted by James Webb to date.
The analysis indicates that around 100 million years ago, the tLRD galaxy underwent a burst of star formation, possibly triggered by an interaction with the Balmer break galaxy. Subsequently, approximately 10 million years ago, the smaller satellite galaxy also experienced a surge in star formation.
Curiously, the intense activity was observed only in the tLRD, not in the Balmer break galaxy, raising questions about the factors driving this phenomenon. Scientists suggest that something beyond gravitational interactions may have influenced this distinct behavior.
One hypothesis proposed by researchers points to the role of the central black hole in the tLRD. Interactions between galaxies often generate bursts of star formation, but the activation of an AGN may occur at a later stage.
In this case, the initial encounter between the galaxies might have stimulated star formation and, with some delay, fed the black hole in the tLRD, leading the galaxy to this transition state. Spectrally, the active black hole in the tLRD exhibits traits of a type I AGN but also shares partial similarities with the red dots, although it lacks a characteristic spectral signature present in most identified LRDs.
The study team emphasizes that if this transition phase is very brief, the likelihood of detecting galaxies in this stage is extremely low. On the other hand, if the transition is more prolonged, future surveys may reveal a greater number of similar objects.
Astronomers plan to conduct further observations of the Stingray system and other LRDs identified in the Canadian NIRISS Unbiased Cluster Survey, aiming to confirm whether the red dots represent a temporary stage in the evolution of systems with black holes, directly influenced by the surrounding environment.
Original published at O Cafezinho.