The early universe continues to be a mysterious frontier, with researchers delving ever further into the first few billion years of the cosmos. A new 3D map of the distribution of galaxies during this period was presented today at the European Week of Astronomy and Space Science in Liverpool.
The new study produced one of the largest maps of the infant universe, taking snapshots of galaxies at 16 different epochs 11-13 billion years ago. That’s between 20 and 7 percent of the current age of the universe. In this map, the international team of researchers discovered almost 4,000 new early galaxies, some of which were the seed that eventually evolved into spiral galaxies like the Milky Way.
“These early galaxies seem to have gone through many more 'bursts' when they formed stars, instead of forming them at a relatively steady rate like our own galaxy," team leader Dr David Sobral, from Lancaster University, said in a statement. "Additionally, they seem to have a population of young stars that is hotter, bluer and more metal-poor than those we see today."
The map was created thanks to telescopes in Hawaii and the Canary Islands. The team used 16 different filters that correspond to the 16 different epochs. Due to the expansion of the universe, the light of galaxies is shifted towards the red. The further away they are, the redder those galaxies appear. The filters focus on specific wavelengths, thus capturing galaxies at specific epochs.
The map is a new important tool in our understanding of galaxy evolution. During those early (billion) years, galaxies began to grow to their present-day size and the rate of star formation was reaching its all-time high. We can learn a lot about modern galaxies by studying those.
“The bulk of the distant galaxies we found are only about 3,000 light-years across in size, while our Milky Way is about 30 times larger. Their compactness likely explains many of their exciting physical properties that were common in the early Universe,” co-author Ana Paulino-Afonso, a PhD student in Lancaster and Lisbon, added. “Some of these galaxies should have evolved to become like our own and thus we are seeing what our galaxy may have looked like 11 to 13 billion years ago.”
The research is published in two papers in the Monthly Notices of the Royal Astronomical Society, and the map is publicly available to use.