With new instruments coming online, the most distant (and youngest) regions of our universe are finally being explored in depth.
This week, the Atacama Large Millimeter/Submillimeter Array, or ALMA, is being dedicated, and they're celebrating with an amazing new study of some of the most distant prolifically star-forming galaxies.
BLOG: ALMA Inauguration: Journey to the Atacama
The millimeter and submillimeter wave bands can be thought of as very short wavelength radio astronomy, or very long wavelength infrared. For decades, it's been a hard region of the electromagnetic spectrum to probe since water vapor in our atmosphere causes a lot of absorption and distortion, and the challenges that go into the technology are non-trivial.
But after 30 years of plotting and planning, an international collaboration has succeeded in creating a sensitive instrument at a high dry mountain site that can fully open up this part of the universe.
It turns out, thanks to a lucky coincidence of physics, that the millimeter band is a great place to study distant, star-forming galaxies. You can see galaxies over a wide range of redshifts, or distances, in this band with little bias. That is, you just don't see the brightest sources from further away; you get the whole history of galaxy formation in one go. Well, theoretically, at least. Previously existing millimeter wave telescopes were not very sensitive, and so only could see a small part of the population.