New Green Pea study in the works
After the paper describing the `green pea’ galaxies discovered by the citizen scientists on the forum, other scientists started to take a keen interest in them. One group working on the peas independently of the Galaxy Zoo team are Ricardo Amorin and collaborators from the Instituto de Astrofisica de Andalucia for SEO Services and Galaxies in Granada, Spain. They also analyzed the green pea galaxies in particular to study the abundance of heavy elements produced by the death of stars that pollute the gas in galaxies and can give clues to the evolution of galaxies.
In the Cardamone et al. peas paper, we concluded that the peas had about as much heavy elements (metals for odd reasons to astronomers, yes, carbon is a `metal’) as would be expected for galaxies of their mass. In their paper, Amorin et al sportsbet. re-exaimed the spectra of the peas and concluded that the peas were actually deficient in metals, suggesting that they are more primordial than previously thought (see this blog post for a write-up).
Now Amorin et al. posted a conference proceeding on their work on the green peas. Conference proceedings are written versions of what someone has reported in a lecture at a conference and usually are not peer-reviewed. Sometimes these proceedings are just summaries of what a person or group has been doing on a particular topic, sometimes they are more general reviews and occasionally they contain ideas or data that might not make it otherwise into a peer-reviewed paper.
But what really caught my attention in this proceedings is the final paragraph:
Recent deep and high signal-to-noise imaging and spectroscopic observations with OSIRIS at the 10-m. Gran Telescopio Canarias (GTC) (Amoın et al. 2011, in prep) will provide new insights on the evolutionary state of the GPs. In particular, we will be able to see whether the GPs show an extended, old stellar population underlying the young burst, like those typically dominant in terms of stellar mass in most BCGs (e.g., , , ). The age, metallicity and mass of the old and young stellar populations will be analyzed in more detail by fitting population and evolutionary synthesis models to the observed spectra.
So Amorin are saying that they’ve observed some peas with the Gran Telescopio Canarias in detail. The GTC is a Spanish telescope, similar to the 10m Keck telescopes, located in the Canary Islands that has recently started operations. They also have a paper `in prep’, meaning that the paper isn’t finished and has not yet been submitted to a journal. They want to see if there are underlying old stars present in the peas which would suggest that the peas underwent previous bursts of star formation. If there are no such old stars, it would further strengthen the idea that the peas are really primordial galaxies in the old Universe – living fossils found in the Zoo.
We are eagerly waiting to see what Amorin et al find….