The images above show three blue compact dwarf galaxies dotted with pink star-forming knots. Just a tenth of the size of the Milky Way, blue compact dwarfs are unique among galaxies with high star-formation rates in that they’re mostly free of dust and have low abundances of metals (elements heavier than helium) — properties they share with galaxies in the early universe. Using Hubble Space Telescope data, Rupali Chandar (University of Toledo) and collaborators investigated the star-formation histories of the three blue compact dwarfs pictured above. The team sought to understand whether these galaxies are all undergoing bursts of star formation, in which new stars are created at 10 times the usual rate. Their analysis revealed that while all three galaxies are forming plenty of new stars, only Haro 11 is truly experiencing a burst; ESO 185 was forming stars about four times faster than normal about 40 million years ago, and ESO 338 hasn’t seen much change in its star formation over the last few billion years. To learn more about the star-formation histories of these peculiar blue galaxies, be sure to check out the full research article linked below.
Citation
“A Tale of Three Dwarfs: Cluster-Based Star Formation Histories of Blue Compact Dwarf Galaxies,” Rupali Chandar et al 2024 ApJ 965 95. doi:10.3847/1538-4357/ad293a