Members of the European Astronomical Society often take advantage of the European Astronomy and Space Science Week to showcase their latest projects. Well, in the 2018 edition, which is held in Liverpool, the presentation of the astrophysicist David Sobral, from the University of Lancaster, in the United Kingdom, and his collaborators, from different institutions, has not exactly been overlooked.
This group of researchers has produced one of the largest three-dimensional maps of the early universe ever built, with data from sixteen different times of the cosmos, between 11,000 and 13,000 million years ago. By itself, this work is already relevant enough to arouse the interest of many of his colleagues, but it is also that, during its elaboration, they have discovered 4,000 ancient galaxies of which nothing was known, many of which would have evolved in Milky Way-like structures.
In a statement, the scientists explain that, for this, they have used the data provided by the Subaru telescope, in Hawaii, and the Isaac Newton, on La Palma. As the light from these ancient galaxies takes billions of years to reach Earth, it could be said that these instruments function as a kind of time machine, with which it is possible to glimpse the evolution of the cosmos in the remote past.
In the late 1990s, astronomers found that the universe is expanding at an ever-increasing speed, which also affects the light coming from these galaxies. In essence, this phenomenon increases your wavelength and causes you to experience what is called a redshift, at the end of the electromagnetic spectrum. This circumstance can be used to deduce the distance at which these objects are and determine their age.
Super compact
Sobral and his team, who detail their findings in an essay published in the Monthly Notices of the Royal Astronomical Society , observed that these unpublished galaxies already existed when the universe was only between 7% and 20% of its current age, which is estimated at about 13,799 million years. Therefore, they hope that their study will shed some light on the mechanisms involved in the formation of these bodies. “In them it seems that the stars are produced in a series of periods of great activity, instead of appearing in a relatively uniform way, as occurs in ours”, indicates Sobral.
These astronomers have also found that they appear to contain populations of young stars, hotter and metal-poor than those seen in most, and that they are remarkably compact. “Its mass extends for about 3,000 light years. The Milky Way, for example, is about 30 times larger. This could explain some of its peculiar physical properties, which could be common in the early universe ”, says researcher Ana Paulino-Afonso, who has also participated in this initiative.
Images: ESO / UltraVISTA / TERAPIX / CNRS / INSU / CASU – David Sobral
Reference: Slicing COSMOS with SC4K: the evolution of typical Lyα emitters and the Lyα escape fraction from z ∼ 2 to z ∼ 6. David Sobral et al. Monthly Notices of the Royal Astronomical Society. DOI: https://doi.org/10.1093/mnras/sty378
