New evidence for the nature of matter from ancient galaxies in the early universe

Astrophysicists in Italy have shed new light on the nature of matter from the James Webb Space Telescope (JWST) that discovered galaxies 13 billion years ago and made numerical simulations of the first galaxies. The study adds another piece to the puzzle of the nature of matter in the universe.

Whereas the generally accepted model of structure formation relies on non-relativistic matter that interacts only with gravity, which is “cold” dark matter, alternative possibilities called for to solve small problems in the standard scenario rely on the hypothesis that dark matter is made of warm particles that have velocity A small non-neglected thermocouple, which is the “warm” dark matter.

“We have found that recent JWST galaxy discoveries in the first part of a billion years after the Big Bang are invaluable investigations into the nature of matter,” says Dr. Umberto Maio, a researcher at the Italian National Institute of Astrophysics (INAF). Astronomical Observatory in Trieste, and lead author of the paper describing the discovery just published in Astronomy and astrophysics.

The research shows that dark matter, the principal constituent of matter in the universe, consists of particles that are either mildly “cold” or “warm” with a mass greater than 2 keV. The study excluded dark matter models with particle masses equal to or lighter than this limit.

While previous work excluded the possibility of differentiating the nature of matter through the use of data in modern times, data from much earlier times and dedicated numerical simulations—the basis of the new study—were needed to provide information about statistical trends for primordial galaxies and break down the decay of models.

“What we’ve done is apply our new and complex numerical application of early galaxy formation to interpret the most recent JWST data,” says Dr. Mayo. “We’ve seen that during the period when the first stars and galaxies formed, the visible properties of structures in the universe depended on the mass of dark matter particles.”

Indeed, the study found evidence that the amount of cosmic star formation, ultraviolet luminosity, and molecular abundances vary across dark matter models, and these differences can be compared with the latest JWST data, the first to arrive in the “old” universe.

The research was a collaboration between the INAF Astronomical Observatory in Trieste and the International School for Advanced Studies in Trieste, Italy. “The study is built on exceptional observations of galaxies in the first half billion years detected by JWST and was released as early as late 2022,” says Professor Matteo Fell of the International School for Advanced Studies in Trieste and co-author of the research. . “This is an important application of scientific data at such primordial times to constrain the nature of dark matter. Thanks to JWST, we have observed the most distant galaxies in the universe and their properties give us clear information about what they are made of.”

This major achievement was enabled by JWST, an international collaboration between the US National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Canadian Space Agency (CSA). The research shows how two observations, the galactic luminosity function and the galactic correlation function at small scales of faint objects, especially when used together, are promising tools for distinguishing between different dark matter models. The results of the study are also consistent with the properties of the galactic medium, the “cosmic web,” of modern times.

“In the future, when more data on small, dim and young sources become available, more hints may come from statistics of early stellar mass and galactic carbon monoxide emissions,” the scientists concluded. The discovery of such early galaxies shows that these structures can only form in a fraction of a billion years – which corresponds to the blink of an eye in cosmic contexts. Thus, more and more discoveries of primordial star-forming galaxies will be possible in the near future, and this will pave the way for a better understanding of the nature of matter.