Despite the infinite cosmic distance, the galaxies scattered throughout the Universe are not isolated islands of matter. Since the birth of the Universe, filaments of dark matter and regular matter have stretched between clusters of matter, connecting everything and everyone into a single web of the cosmic web. To date, such filaments have been observed only near “universal lanterns” – quasars. But now scientists have a tool to detect threads anywhere in the Universe.
California Institute of Technology astrophysicist Christopher Martin has developed a technique and tool to directly image the cosmic web even in dark corners of the Universe, such as during the early stages of the process. evolved, when there were fewer stars and galaxies and, therefore, very little radiation capable of illuminating the filaments of the cosmic web. During this time, these threads stretched from the past and transformed, becoming conductors of matter in the Universe and tools for its evolution. About 60% of the primordial hydrogen created after the Big Bang is thought to be concentrated in the filaments of the cosmic web. They absorb hydrogen from the intergalactic medium and transfer it to galaxies to stimulate star formation. Mapping these routes will tell us a lot about the past evolution of the Universe and will allow us to model its future evolution. But to do this, it is necessary to solve a problem: cold hydrogen atoms in the intergalactic medium form an extremely weak source of radiation, almost impossible to record with instruments on Earth. .
A Caltech researcher ran simulations in 2019 and figured out how he could detect the cosmic web even in the darkest corners of the Universe. Hydrogen radiation was recorded along the Lyman-alpha line, and background radiation, which did not allow detection of the useful signal, was subtracted in the process of comparing signals from different parts of the sky. In fact, the adder acted as a filter for the useful signal. So at the telescope. Keck Cosmic Web Imager (KCWI) appeared in Hawaii.
The device takes into account the shift of light to the red range of the spectrum, which makes it possible to monitor changes in the cosmic web in time, and not just in space. Based on the observations made, the scientist built a real 3D model of the evolution of the cosmic web in a region of space where it had never been illuminated by anything – in the period from 12 to 10 billion years ago. And this is the right decision – to begin to unravel the tangle of the evolution of the Universe from the moment when there were relatively few threads.
“We are very pleased,” said one of the astrophysicist’s colleagues at the institute, “that this new instrument will help us learn about more distant filaments and about the era of the formation of the first stars and black holes.”