A team of University of Copenhagen astrophysicists has arrived at a major result regarding star populations beyond the Milky Way.
The result could modify our understanding of a wide range of astronomical phenomena, including the formation of black holes, supernovae plus why galaxies die.
For as long as humans have studied the heavens, how stars look in distant galaxies is a mystery. In a study released today in The Astrophysical Journal , the team of researchers on the University of Copenhagen’s Niels Bohr Institute is challenging previous understandings of stars beyond our own galaxy.
Since 1955, it has been assumed that the composition associated with stars in the universe’s various other galaxies is similar to that of the hundreds of billions of stars inside our own— a mixture of massive, medium mass and low mass stars. But with the help of findings from 140, 000 galaxies across the universe and a broad variety of advanced models, the team has tested whether the exact same distribution of stars obvious in the Milky Way does apply elsewhere. The answer is no. Stars in distant galaxies are typically more massive than those within our “ local neighborhood. ” The finding has a major impact on what we think we know about the universe.
“ The mass of stars tells us astronomers a lot. If you change mass, additionally you change the number of supernovae plus black holes that occur out of enormous stars . As such, the result means that we’ll need to revise many of the things we all once presumed, because remote galaxies look quite completely different from our own, ” says Albert Sneppen, a graduate pupil at the Niels Bohr Company and first author from the study.
Analyzed light from a hundred and forty, 000 galaxies
Researchers assumed which the size and weight associated with stars in other galaxies had been similar to our own for more compared to fifty years, for the basic reason that they were unable to see them through a telescope, because they could with the stars of our own own galaxy.
Distant galaxies are vast amounts of light-years away. As a result, just light from their most powerful stars ever reaches Earth. This has been a headache for researchers around the world for years, as they could never accurately clarify how stars in other galaxies were distributed, an uncertainty that forced them to think that they were distributed much like the superstars in our Milky Way.
“ We’ve only been able to see the tip from the iceberg and known for a long time that expecting other galaxies to look like our own was not a particularly good assumption to generate. However , no one has ever been able to prove that other galaxies form different populations of stars. This study has allowed us to do exactly that, which may open the door for any deeper understanding of galaxy formation and evolution, ” states Associate Professor Charles Steinhardt, a co-author of the research.
In the research, the researchers analyzed light from 140, 000 galaxies using the COSMOS catalog, a substantial international database of more than one particular million observations of gentle from other galaxies. These galaxies are distributed from the closest to farthest reaches from the universe, from which light offers traveled a full twelve billion dollars years before being visible on Earth.
Massive galaxies die very first
Based on the researchers, the new discovery will have a wide range of implications. For example , this remains unresolved why galaxies die and stop forming new stars. The new result shows that this might be explained with a simple trend.
“ Now that we are much better able to decode the bulk of stars, we can see a brand new pattern; the least massive galaxies continue to form stars, while the more massive galaxies stop birthing new stars. This suggests a remarkably universal tendency in the death of galaxies, ” concludes Sneppen.