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The chemical fingerprints of galaxy formation

Final Activity Report Summary - GALCHEM (The chemical fingerprints of galaxy formation)

One of the great challenges of 21st century science is providing a clear understanding of our place in the Universe, in particular how this "island" on which we live - the Milky Way Galaxy - came to possess the physical characteristics which define its age, colour, chemistry, and gas and star light distribution. The underlying physics governing galaxy formation, its subtle interplay between gravity and fluid dynamics, links in directly to the fundamental physics governing many day-to-day aspects of life, including atmospheric physics, climate modelling, aerospace and automotive engineering, and orbital dynamics of communication satellites.

During the course of this unique project, we were successful in blending a programme of observational analyses of the stellar populations of galaxies and the simulation of these galaxies using high performance computational techniques. Such a balanced programme of research (rather than one emphasising one over the other) is a challenge, and a testament to the skills of the Marie Curie Fellow. Highlights of our work include the first successful cosmological simulation of a Milky Way-like galaxy using what is called a "grid" code; with this work, we have been able to demonstrate graphically how stars like the Sun, born elsewhere in the Milky Way, may have migrated substantially from their birth place to their current location. We have also proposed a new paradigm for globular cluster (ancient clusters of stars orbiting the Milky Way) formation and evolution which appears to address many of the shortcomings of extant theories.

Our work on simulating the distribution of isotopes in the early Universe calls into question the need for additional sources of heavy isotopes of carbon in the local Universe, in contradiction to conventional wisdom. Our observational work, conducted in parallel with our computational efforts have shed light on the formation and evolution of the brightest and most massive galaxies in the Universe - those lurking at the hearts of rich clusters of galaxies. In addition, we have searched for (and found!) signatures of recent galactic cannibalism of satellite "neighbours" in the stellar light of massive galaxies.