The first galaxies of the Universe were formed like the Milky Way

Monday, 15 January 2018

Valentino González
Astrónomo DAS - U de Chile

The data obtained allowed an international team of astronomers to determine that the gas in these "newborn" galaxies rotated in a whirling motion, similar to what happens in the Milky Way and in other galaxies formed much later in the history of the cosmos. The researchers also found that despite their relatively small size, these galaxies were forming at a higher rate than other younger galaxies.

Valentino González, academic of the Department of Astronomy FCFM Universidad de Chile and member of the research team, explains that looking at these objects that are billions of light-years away allows us to look back in time and analyze the formation of galaxies more early. "At the beginning of the Universe there is only gas, which is forming stars and things move in a random, more chaotic way, But the fact that these two galaxies look like a disk similar to our Milky Way,and be able to observe the internal movement of the gas that fueled their growth, tells us that the dynamics of these things is different: they are sorted and start to rotate in this way ordered much earlier than we thought", he says.

The selection of the galaxies was not random. Thanks to the Hubble Space Telescope, you have already had some information about these objects, such as the approximate distance to which they were. "This distance is important because it corresponds to an epoch in which the hydrogen of the Universe Change of state initially, the hydrogen was neutral and quickly become ionized, so study the galaxies of that time is interesting," he says.

For the researchers, the results were quite a surprise. "Actually, what we were expecting was eleven in very disordered galaxies, if one looks at numerical simulations at the beginning of things are very chaotic, even when one looks at the local universe, the galaxies that are very small tend to be very disordered systems The fact that we have observed these two galaxies, which seems to be an ordered disk, that turns to that is some other mechanism that the gas joins and forms galaxies that we have not considered, "he explains.

The results of the study led by Dr. Renske Smit, of the Kavli Institute of Cosmology (University of Cambridge), is now available on the Nature Astronomy website https://www.nature.com/articles/nature24631. They are also presented at the 231st meeting of the American Astronomical Society.