Back in March I was speaking to a colleague of mine in Nottingham, Seb Foucaud, about the Galaxy Zoo Peas, and showing him Carie’s paper. Seb works primarily on very distant (high redshift) massive galaxies, often using data from the UKIDSS Ultra Deep Survey. He quickly noticed that the way Carie selected Peas from SDSS data was very similar to the way they select high redshift galaxies, except that the exact colours used were different, as more distant galaxies are redder.
What this meant was that he already had an excellent dataset for searching for objects equivalent to the SDSS Peas, but at higher redshifts. With the deadline for telescope proposals just a few weeks away, it seemed like a good opportunity to put together a case for getting more detailed spectroscopic observations for a sample of these objects. The first aim is simply to confirm the redshifts of these galaxies, to make sure they are what they think they are. The second is to find out more about them, in particular how fast they are forming stars and their chemical make-up, so we can compare them with the SDSS Peas and work out if they really are the same kinds of object.
Finding more distant versions of the Peas will be very helpful to understanding exactly how they compare to apparently similar galaxies that were rapidly forming stars in early in the history of the universe. If we can demonstrate convincing links between the populations, then we can use the nearby SDSS Peas to study the processes that built up some of the earliest galaxies, which are too far away to permit detailed study.
So, with all that in mind I set about working out which telescope would be most suitable, checking the feasibility and writing the proposal, with input from a few other members of the Galaxy Zoo and UDS teams, while Seb worked on refining a way of selecting good candidates from his data. We decided to ask for time on the NTT, at La Silla Observatory in Chile, using the instrument EFOSC2. The proposal was submitted to ESO on 31st March, and since then we’ve been waiting to find out the decision. We finally heard back from ESO this week, and as you may have guessed, we’ve been successful. The comments noted that the proposed observations are somewhat speculative, which they are given we don’t know for sure that the Pea selection will work well at higher redshift. However, given the potential for some very interesting results, we have been allocated 5 nights observing in November. I’ll let you know how it goes!