Parts of Missing Cosmic Matter Found

The discovery proves the assumption that 80-90 percent of ordinary matter is located outside galaxies.

An multi-national research team has snapped images of the previously elusive galactic wind for the first time. This unique observation made it possible for the first time to record the existence of baryons, which are theoretically considered the missing substance of the Universe. The discovery was made with the MUSE instrument mounted on ESO’s Very Large Telescope (VLT).

Mapping a galactic wind and discovering the location of the universe’s missing ordinary matter

For the first time, the team was able to capture the so-called galactic wind and plot it on a map. In their study, astronomers explain that galaxies have the ability to exchange matter with the environment due to galactic winds created by stellar explosions.

Until now, this phenomenon has been well known from theoretical predictions and simulation results. The authors of the work compare galaxies with islands of stars in the Universe. It is known that they consist of ordinary (baryonic) matter, which in turn consists of the elements of the periodic table known to us, and dark matter, the composition of which is a complete mystery for scientists.

However, there are many secrets associated with ordinary matter. For example, while studying the formation of galaxies, scientists are faced with the following problem: up to 80 percent of the baryons that make up ordinary matter disappear somewhere.

Earlier computer simulations have shown that these missing baryons could have been pushed out of galaxies into intergalactic space by the aforementioned galactic winds created by stellar explosions.

Until recently, it was not possible to verify this assumption in practice. In a new study, astronomers have succeeded in doing this. Using the VLT, they made observations of the galaxy Gal1, and the nearby quasar served as a kind of cosmic “beacon”, helping to focus the observations.

One of the main goals of this study was to study the nebula around the Gal1 galaxy. The authors of the work admit that they did not really count on success, since the characteristics of the nebula were unknown. Scientists did not even have data on the degree of its luminosity.

However, they were in a sense lucky, since the location of the galaxy and the quasar turned out to be ideal for observations from Earth. As a result, it was possible to record the processes of gas exchange caused by galactic winds.

Then, based on the data obtained, a unique map was created, on which the galactic wind was marked for the first time.

In fact, astronomers were the first to observe an emerging nebula that simultaneously emits and absorbs magnesium – this is one of the missing baryons in the universe. Magnesium is exchanged between the Gal1 galaxy and its outer surroundings.

Thus, scientists have discovered some of the missing baryons of the universe. The discovery confirms the assumption that 80-90 percent of ordinary matter is located outside galaxies.


Forbes India.


Discovery of a MgII emission halo probed by a quasar sightline. Monthly Notices of the Royal Astronomical Society.

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