Though scientists have long suspected that dwarf galaxies were responsible for a large number of the stars we now see in the universe, they had never had way of measuring just how rapidly these galaxies produced new stars. Until now.
Infrared Wavelengths of Wide Field Camera 3
Though new stars are forming throughout the galaxy every day, most of the stars that now exist were created between two and six billion years after the Big Bang. Dwarf galaxies—(relatively) low mass clusters of billions of stars that are too small to be regular galaxies and too big to be standard star clusters—were long thought to be the source of these stars.
Now, newly collected data from the Hubble Telescope’s Wide Field Camera 3, which forms images from infrared wavelengths, has allowed scientists to study a number of “starburst” dwarf galaxies. Starburst galaxies are those that form stars at far higher rates than do “normal” galaxies.
“These galaxies are forming stars so quickly that they could actually double their entire mass of stars in only 150 million years,” said Jean-Paul Kneib of the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, and co-author of the study. “This sort of gain in stellar mass would take most normal galaxies 1-3 billion years.”
Rare Starburst Galaxies
Starburst galaxies are rare, as their accelerated star production is likely caused by a chaotic cosmic event such as a galactic merger or the shockwave from a (relatively) nearby supernova. Scientists have not yet been able to definitively prove this, however.
Now that they can study these galaxies more closely, researchers hope to understand how they formed and behaved early on, and hopefully discover why their star output is so great. This could, in turn teach the scientists more about galactic growth and evolution, and how stars formed in the first epochs after the Big Bang.
The EPFL team’s full report was published in the June 19, 2014 edition of The Astrophysical Journal (vol. 789, No. 2).
- National Geographic: “Dwarf Galaxies in the Early Universe Worked Overtime Making Stars”
- Sci-News.com: “Hubble Observations Shed New Light on Star Formation in Early Universe”