One of the most fundamental parameters of a galaxy is its stellar mass. Unfortunately, it’s been very hard to measure these for the SPT dusty galaxies I’ve been studying – since they’re lensed by foreground galaxies, the light from the foreground galaxy can totally swamp the light from the background galaxy we care about (this isn’t an issue at long wavelengths, because the lens galaxies usually have almost no dust emission). This paper pulled together the deblending technique we developed previously on a single object and applied it to a larger sample.
We found that all of the galaxies we looked at are forming new stars at (specific) rates much higher than other galaxies at the same time in the history of the universe (in astronomer-speak, they’re above the “main sequence” of galaxies). This probably means all of these galaxies are experiencing strong starbursts – as of yet, we don’t know why.