2023-07-08 14:45:23
Thanks to the James Webb Space Telescope, astronomers may have discovered one of the oldest strands of the “cosmic web,” dating back 830 million following the Big Bang, when the Universe reionized. Three million light-years long and punctuated by 10 galaxies, this strand appears to be anchored within a primeval quasar — an ultra-bright galaxy powered by a highly active supermassive black hole.
In the Universe, galaxies are not randomly distributed, but come together in clusters and interconnected filaments, forming what is known as the “cosmic web”. Filaments link galaxies together on megaparsec scales (1 megaparsec equals 3.26 million light-years). Like a veritable spider’s web, between the strands resides the cosmic void. Over time, this web becomes ever more visible as gravity condenses matter into it, making astronomical observations easier.
A strand attached to a quasar
The cosmic web predicts the distribution of most of the gas in the intergalactic and circumgalactic mediums (the gaseous medium surrounding the galaxies). This complex regulation, as well as the rejection of matter resulting from the feedback processes of cosmic objects (stars, galaxies, black holes, etc.), would play a key role in controlling the growth of galaxies throughout the Universe.
An invitation to dream, ready to be worn.
Over the past few decades, the intergalactic medium has been widely explored in order to trace the filaments of the cosmic web. However, observations were restricted to a few particular regions, the range and capacity of observation devices of the time being limited to scales of a few megaparsecs. The raked regions are not very representative of the entanglement of filaments at the level of which galaxies are born and are distributed.
in 2021, researchers have traced some filaments of the cosmic web located between 1 and 2 billion years following the Big Bang. But the James Webb Space Telescope is a big game-changer, extending observations to much larger scales.
Using their state-of-the-art observing devices, a group of astronomers discovered a thread-like arrangement of 10 early galaxies, which would have formed around 830 million years following the Big Bang (in the midst of cosmic reionization ). At the end of the filament, 3 million light-years long, seems to be attached an extremely luminous quasar.
« It is one of the first filamentous structures ever found associated with a distant quasar “, explains in a communiqué Feige Wang of the University of Arizona in Tucson, lead author of the study, published in The Astrophysical Journal Letters. The team of experts estimates that the filament will evolve into a massive galaxy cluster similar to the gigantic Coma cluster, comprising more than 1,000 galaxies and located 330 light years from Earth. This filament might also be one of the oldest in the cosmic web.
A possibility of evolution into a massive galactic cluster
The researchers discovered the famous filament thanks to the quasar to which it is attached. They were surprised to discover a surprisingly long and thin structure, spanning millions of light-years. ” I expected to find something, but I did not expect such a long and thin structure said study co-author Xiaohui Fan, also an astronomer at the University of Arizona.
The quasar was discovered as part of the ASPIRE (A Spectroscopic Survey of Biased Halos in the Reionization Era) project, aimed at studying a set of 25 quasars from the reionization epoch (from 700 million years following the Big Bang). Experts suggest that supermassive black holes, whose accretion fuels quasars, may have participated in the formation of the cosmic web, acting like gravity wells gathering and stretching matter to form filaments. Notably, gravity would keep these strands connected together.
Moreover, previous simulations suggest that the reionization quasars, at least a billion solar masses, formed within huge clusters of dark matter and grew by accretion or by merging with other clusters. In this context, one would expect early quasars to be found within large-scale (megaparsec) galactic overdensities.
Want to remove ads from the site while continuing to support us?
It’s simple, just subscribe!
Right now, 20% discount on the annual subscription!
However, uncertainty regarding the redshift of previously observed quasars clouded the clues that might indicate overdensity signals. James Webb’s performance allowed researchers in the new study to discover that the quasar they detected (the one anchoring the filament) was embedded in an overdense galaxy — one of the most overdense structures known in the Universe. primitive, and might evolve into a massive cluster (like the Coma cluster).
A second part of the study suggests that the black holes powering these early quasars have masses ranging from 600 million to 2 billion solar masses. Although the reasons for these extreme characteristics are still unknown, experts propose a hypothesis where two criteria must be met. The first criterion includes the “germination” of the black hole from a massive “seed” of at least one thousand solar masses. The second criterion implies that the seed must have accumulated very quickly at least a million times more material throughout its life.
If these supermassive black holes accumulate matter, they can also eject it and fuel winds spanning intergalactic scales. These winds can have a significant impact on the formation of stars within the galaxies, at the center of which they reside. Webb’s data would be the best evidence to date supporting this hypothesis. In particular, the researchers discovered that the winds of black holes at the center of massive galaxies are a kind of reservoir feeding their growth. Until now, these winds have only been observed in the neighboring Universe, but never at the time of reionization.
Source : The Astrophysical Journal
Letters
1688870404
#James #Webb #detects #strands #cosmic #web #formed #million #years #Big #Bang
