A few days ago, my tennis teammates said to me, “Hey Jairo, how come there are so many new discoveries about very distant galaxies right now?” “Finally an easy question,” I thought, “since we didn’t have a 20-foot telescope in space before!” On this occasion, they referred to the discovery of the oldest known black hole, a result published last week in the journal Nature. They asked me if I participated in the work. “Unfortunately not,” I told them, “but my colleagues from the Madrid Astrobiology Center, with whom we recently discovered the most distant analog galaxy of the Milky Way to date, were in attendance.” This gave me an opportunity (you see I don’t need much) to chat with them a bit more about the JWST Space Telescope and this latest work I’m bringing you today in this astrophysics outlet.
“JWST Most Distant Milky Way-Like Galaxy Ever Observed Is Identified,” was the title of a press release we issued a few months ago. I imagine this headline won’t mean much to some, so let me briefly explain the implications it has for those of us, like me, who study life in galaxies. In fact, this discovery can be divided into two: on the one hand, we were able to detect the most distant barred galaxy to date, and on the other hand, it turned out that this galaxy has the mass and structure of the Milky Way. those first moments of the universe.
As we’ve discussed in other posts in this drawer, the most massive spiral galaxies in the nearby universe show an elongated bar-like structure running through their center, just like our own galaxy, the Milky Way. However, theoretical models predict that the physical and dynamical conditions of the early universe do not favor the formation of bars in the youngest and most distant galaxies. Using JWST images, we discovered the barred spiral galaxy ‘ceers-2112’ when the universe was only 2.1 billion years old, challenging our previous understanding of the formation of these structures. In particular, this finding proves that when the universe was still very young, the central regions of this galaxy were already dominated by baryons (the ordinary matter of which we are composed) and not by dark matter, as previously thought.
We currently estimate the age of the universe to be around 13.8 billion years, and until now scientists believed that the structure of spiral galaxies like the Milky Way was not consolidated until the universe reached half its current age. However, the discovery of ceers-2112, a galaxy analogous to the Milky Way, reveals that Milky Way-like galaxies existed as early as 11.7 billion years ago, when the universe was only 15% of its current age. Until now, we believed that the conditions of the early universe only supported the formation of irregular structures, the result of very violent episodes of star formation and a greater probability of mergers between galaxies. However, the discovery of ceers-2112 shows that the stabilization of the Milky Way into an “orderly” disk of stars rotating around its center may have occurred on shorter time scales than expected.
Investigating how galaxies acquire their structure and evolve over time is essential to understanding the physical processes that take place since their formation. With the JWST space telescope, for the first time, we have the technology and equipment necessary to study the morphology of very distant galaxies in detail, so get ready, my training partners, because, between obstacle and volley, I’ll continue to tell what we’ve discovered about the life of galaxies in the early universe.
Jairo Méndez Abreu was born in San Juan de la Rambla, Tenerife and completed his Bachelor’s degree in Physics at the University of La Laguna (ULL). He holds PhDs in astrophysics from ULL and the University of Padua, Italy. After time spent in Italy, he returned to the Canary Islands with a postdoctoral contract at the Institute of Astrophysics of the Canary Islands (IAC) and a contract with Juan de la Cierva. He later went to Scotland to do his research at the University of St Andrews and returned to IAC to work on the design and scientific use of the WEAVE instrument. After a period at the University of Granada, he currently works at ULL and is the main investigator of the BEARD project.
* The section is coordinated by Adriana de Lorenzo-Cáceres Rodríguez
