ADS: Aravena et al. 2013
arXiv: Aravena et al. 2013
New stars form out of gas which is mostly molecular hydrogen, but unfortunately it’s really difficult to observe directly. Instead, we use other molecules as tracers of the molecular gas. The most famous tracer is the lowest rotational transition of carbon monoxide, CO(1-0), which can give you a rough idea of the total quantity of molecular gas present in a galaxy and thus its “fuel tank” for future star formation.
In this paper, we presented Australia Telescope Compact Array observations of two SPT galaxies at redshift z = 2.7. Using these observations, we determined that the galaxies have around 170 and 320 billion suns’ worth of molecular gas in them. But, they’re also forming stars so quickly that they would run out of gas in less than 50 million years if they can keep up such a high rate of star formation (this sounds like a long time, but is much faster than galaxies normally evolve).