ArXiv: Bethermin et al. 2016
One of the great benefits of studying gravitationally lensed galaxies is that you can get a lot more bang for your telescope buck than otherwise possible – the source is magnified, so it appears brighter and takes much less time to observe any given diagnostic. In this letter, Matthieu Bethermin synthesizes a lot of ALMA observations we’ve acquired for one particular galaxy, SPT2132-58, to demonstrate what’s possible when many measurements are available.
SPT2132-58 is magnified by a factor of about 6, and our collection of observations includes a lot of the highlights that have been observed in a bit of a scattershot fashion for may high-redshift sources: a range of CO transitions, the ground-state CI line, CII, and the critical-yet-faint NII line at 205um.
Matthieu finds that, in spite of existing at a time when the universe only a little over a billion years old, the gas in SPT2132-58 is already enriched with heavy elements at a level comparable to our own sun, which wouldn’t form for about another 8 billion years. He also finds that the CO emission in SPT2132-58 hints that the galaxy is experiencing some process which is driving the CO to be highly excited. This might mean that some region in the galaxy has a particularly strong radiation field from young stars, or that it hosts an active galactic nucleus, feeding a central supermassive black hole.