arXiv: Bothwell et al. 2013b
This paper presents a comprehensive, multi-wavlength view of one SPT dusty galaxy which we’ve studied in a lot of detail. The goal was to pull together everything we knew about this particular galaxy to demonstrate the level of detail you can get for a large sample of lensed galaxies. We also introduced a snazzy technique to deblend the foreground lens emission from the background source emission in low-resolution images from the Spitzer IRAC instrument.
From several lines of evidence, it looks like SPT0538-50 is actually two galaxies in the final stages of merging to become one larger galaxy – this collision is what’s causing it to form stars so rapidly. The galaxy sits a factor of ~5x above the “main sequence” of galaxies – it’s forming stars about 5x faster than most other galaxies with the same mass of stars. We found several spectral lines of water and high-excitation CO lines, which both suggest that the star formation is ongoing in compact, dense regions, in agreement with the lens model we derived from our ALMA images.