A "starburst galaxy" is a type of galaxy that has a lot of new star formation happening at a very fast rate. It is like a burst of stars being born. Full definition
By contrast, the SFRs of starburst galaxies reach ten, or even a hundred to a thousand solar masses per year. (sciencedaily.com)
The research is described in the paper «Dusty starburst galaxies in the early Universe as revealed by gravitational lensing», by J. Vieira et al., in the journal Nature. (alma-telescope.jp)
Some possible scenarios: incredibly massive black holes erupting in jets of matter, galaxies colliding or star - producing factories known as starburst galaxies. (discovermagazine.com)