Astronomers learn and discovers how galaxies form through galactic mergers

In the United Kingdom (UK), astronomers announce that they find how galaxies such as the Milky Way formed over more than 10 billion years through multiple varieties of galaxies colliding together. Galaxies are the largest single islands in the universe in which their origin of how they form or evolve is a very old question but also isn’t filled with easy answers. A major study submitted this week to the American Astronomical Society’s The Astrophysical Journal has come up with a solution to address this issue.

Astronomers led by Professor of Extragalactic Astronomy Christopher Conselice at the university, suggest that a long study of galaxies and how they formed through a period of more than 10 billion years shows that these galaxy mergers are important aspects of forming galaxies. According to the researchers, the average galaxy over 10 billion years will undergo formation around other galaxies through 3 galactic mergers, which will more than double that galaxy’s mass.

Professor Conselice stated” This also suggests that our galaxy has likely undergone at least one of these significant mergers during its history, which radically changed its shape and formation history,” Mergers, such as the ones in this study, trigger star formation, which may be the origin event for how stars including our Sun formed, as well as feed the matter that feeds central black holes.”

Galaxies appear and form in different sizes and shapes in the universe. For example, some galaxies like our own are spiral or barred spirals and are very massive with billions to even trillions of stars. While other galaxies are enormous islands of stars with spheroidal or ellipsoidal structures with no specific forms. Galaxy merging is one way in which galaxies can grow in mass since it’s a process that occurs when two or more galaxies collide together. Galaxy mergers have always been known however, their roles in how astronomers obtain massive galaxies seen today has always remained a big mystery and an important question in cosmology.

The results of this study start back from observing back over 10 billion years of the galaxies that are in “pairs” or close presence. Galaxies that are very close in distance will eventually merge to form a new galaxy over a billion years. By observing galaxies in the merging process, this study determined the history of galaxy merging and therefore, the history of galaxy formations in the universe. “Due to the total number of galaxies in the universe, over the past 10 billion years, about 2 trillion of these mergers events would have occurred” stated Professor Conselice.

Unknown galaxy merging history shall allow astronomers to understand more about galaxies that haven’t been addressed before. Future studies by Professor Conselice’s team and others will show the hint for this finding for a crucial understanding of the development of new stars and black holes in galaxies over this cosmic event.