SANTA CRUZ DE TENERIFE, Nov. 8 (EUROPA PRESS) –
An international scientific team, in which researchers from the Institute of Astrophysics of the Canary Islands (IAC) and the University of La Laguna (ULL) participate, have found a barred spiral galaxy analogous to the Milky Way in the early Universe, when it had only one 15% of your current age.
The galaxy, called ceers-2112, is the most distant ever observed and its existence challenges the current model of galactic formation and evolution. The discovery, made with data from the James Webb Space Telescope (JWST), is published in the journal Nature.
In astrophysics, the study of the structure of galaxies at different distances, that is, at different ages of the cosmos, is essential to reconstruct the history of the formation and evolution of the Milky Way. In the nearby Universe, most massive spiral galaxies show an elongated bar-shaped structure in their central regions, just like our own galaxy. These bars play a fundamental role in galactic evolution, since they favor the mixing of elements, essential for the formation of stars.
However, according to the predictions of theoretical models, the physical and dynamic conditions of the early Universe do not favor the formation of bars in the youngest and most distant galaxies. For this reason, it was thought that the structure of spiral galaxies like the Milky Way was not consolidated until the Universe was half its age, which is currently 13.8 billion years old.
Now, a team led by the Center for Astrobiology (CAB), CSIC-INTA, has discovered a galaxy in the early Universe that has a galactic bar similar to that of the Milky Way. The observations, made with JWST, show a barred spiral galaxy when the Universe was just 2.1 billion years old, challenging previous knowledge about galaxy formation.
“Contrary to what was expected, this discovery reveals that galaxies similar to the Milky Way already existed 11.7 billion years ago, when the Universe was only 15% of its current age,” says Luca Costantin, CSIC postdoctoral researcher at the CAB. from Madrid and main author of the article.
This barred spiral galaxy, called ceers-2112, also has the same mass that the Milky Way must have had at that moment in the Universe. According to the scientific team, an important conclusion emerges from this fact: “Surprisingly, this finding proves that when the Universe was still very young, the evolution of this galaxy was dominated by baryons, the ordinary matter of which we are composed, and not by dark matter, although the latter is more abundant,” says Jairo Méndez Abreu, researcher at the ULL and the IAC, and co-author of the study.
A REVOLUTIONARY TELESCOPE
Until now, knowledge about the morphology of distant galaxies was based mainly on studies carried out with the Hubble Space Telescope (HST), which revealed very irregular structures, the result of possible mergers between galaxies. However, the extraordinary capabilities of JWST are revolutionizing astrophysics and revealing a distant Universe that is not exactly as expected.
“For the first time, with James Webb we have the technology and instrumentation necessary to study in detail the morphology of very distant galaxies, so we expect, in the coming years, an unprecedented transformation of our knowledge about the processes of formation and galactic evolution,” underlines Marc Huertas-Company, a researcher at the IAC and the ULL who also participated in the study.
The bar galaxy ceers-2112 has been identified thanks to the analysis of images taken with the NIRCam instrument at JWST. The scientific data was taken during observations by the CEERS (Cosmic Evolution Early Release Science, led by Steven L. Finkelstein of the University of Texas, USA) project within the Extended Groth Strip, a region of the sky located between the constellations of Ursa Major. and the Boyero. 33 researchers from 29 institutions in 8 countries have participated in the project.
