A collaborator in France rung me up a couple of years ago asking if I wanted to be involved in a project using Planck satellite data. This sounded so exciting I said yes first and thought
about it later. Luckily, it turned out to be a good opportunity.
The reason for the quick reaction is partly because Planck satellite data is not open to U. S. astronomers, so this invitation is one of the only ways to get access to this outstanding dataset.
The Plank science team have recently made the headlines by measuring global parameters of the universe such as its mass, density and size. I was called in instead to find actual objects in space using Planck.
We had figured out that Planck might be especially good at picking out baby groups and clusters of galaxies. This is because baby clusters will be shining at exactly the color at which Planck sees, which is the sub-millimeter (close to microwaves used to heat up our food)!
Planck is a great telescope for such a project also because it operates in space and so can see the entire sky. We searched the entire sky for colors indicative of baby clusters, and then took our best 200 cases and observed also with a different satellite called the Herschel Space Observatory (Herschel).
Herschel is also owned by Europe but in this case some clever folks in the U. S. made a monetary contribution to grant us access to the dataset. When we viewed our 200 brightest large objects with Herschel with its higher pixel resolution we saw that most of the objects are indeed the baby clusters we had hoped to find all along.
We had hoped to find them because we see a lot of old clusters of galaxies close to our own Milky Way galaxy today. If there are old ones, then they must have been young at some point, and by looking to greater and greater distances we can see back in time.
The results have come out in press releases worldwide, such as the University of Arizona news: http://uanews.org/story/galaxy-clusters-formed-as-fireworks, Wired magazine: http://www.wired.com/2015/04/photos-astronomers-find-hundreds-baby-galaxy-clusters/ and others.