Since the James Webb Space Telescope (JWST) began exploring the early Universe, astronomers have identified peculiar “little red dots” (LRDs) in its infrared images. These compact entities, numbering in the hundreds, exist at a high redshift, approximately 12 billion light-years away. Scientists estimate these dots formed around 600 million years after the Big Bang, marking them as significant components in the Universe’s infancy. They appear red in optical light and blue in the ultraviolet spectrum.
The origins and nature of these strange objects have sparked various theories. One possibility is that LRDs represent light emitted from regions surrounding supermassive black holes concealed by dense gas clouds. However, this theory is at odds with the visibility of rapidly growing supermassive black holes from that era, as most observed are not obscured by gas clouds. Others have speculated that LRDs might be an unexplained form of early galaxies.
Another suggestion is that they are a type of active galactic nucleus, typically powered by black holes, as their emissions indicate such a connection. Alternatively, LRDs might be supermassive metal-deficient stars, termed “black hole stars,” which lived briefly by stellar standards.
In a recent study, a team of international astronomers analyzed data from the Chandra X-ray Observatory alongside a JWST deep survey. They discovered an unusual LRD emitting X-rays from about 11.8 billion light-years away, a finding that sets it apart from other LRDs, which do not emit X-rays. This object, named 3DHST-AEGIS-12014, emits X-rays similar to those from black hole accretion disks and jets.
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It is plausible that this unusual object serves as a link between black hole stars and the growing supermassive black holes that emerged in the early Universe.
What Exactly Is 3DHST-AEGIS-12014?
The X-ray emitting LRD is small, appears red like its counterparts, and exists in the Universe’s early stages. Its X-ray emissions, however, suggest it is different from other LRDs. The current best theory is that it could be a transitional object indicating the presence of a black hole.
Even if it represents a transitional LRD form, questions about its formation, evolution, and ultimate state remain. Anna de Graaff of the Harvard-Smithsonian Center for Astrophysics noted, “If little red dots are rapidly growing supermassive black holes, why do they not give off X-rays like other such black holes?” She said, “Finding a little red dot that looks different from the others gives us important new insight into what could power them.”
Delving into Transitional Phases
The observational team’s paper suggests the X-ray LRD might be evolving into one of the early-type growing black holes scattered throughout the early cosmos. It could be enveloped in gas clouds that absorb or block other light forms. Occasional openings in the clouds might allow X-rays to pass through intermittently, explaining the variable X-ray emissions from 3DHST-AEGIS-12014.
Co-author Hanpu Liu of Princeton University remarked, “If we confirm the X-ray dot as a little red dot in transition, not only would it be the first of its kind, but we may be seeing into the heart of a little red dot for the first time.” He continued, “We would also have the strongest piece of evidence yet that the growth of supermassive black holes is at the center of some, if not all, of the little red dot population.”
Given that LRDs, especially this one, exist in the Universe’s early epochs, other theories must be considered. One idea is that 3DHST-AEGIS-12014 could be a growing supermassive black hole within a forming galaxy, possibly obscured by an exotic type of dust not previously detected by astronomers.
To address the numerous questions about 3DHST-AEGIS-12014, further observations are necessary to gather time-variable data on its behavior and development.
This article was originally published by Universe Today. Read the original article.
