ELUCID - Exploring the Local Universe with Reconstructed Initial Density Field

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

The nearby universe shows clumpy structures, such as stars and planetary systems, galaxies, and clusters of galaxies, arranged in a beautiful yet complex cosmic web. The distant, early universe appears much smoother. The question of how clumpy structures formed from a smooth early universe remains an exciting astrophysical mystery. Furthermore, the interaction of galaxies and their surrounding intergalactic medium is also a matter of intense current research. This project addresses important questions about the formation of structure in the universe over 14 billions years of cosmic history. The researchers will seek to answer questions that include: What drives the formation of the large-scale structure we observe and how do galaxies like the Milky Way form and evolve in the cosmic web?  Are simple physical laws as we understand today able to reproduce the complex structures in the vast cosmos, as well as their interaction with each other? The project will also support the work and professional training of a graduate student in astrophysics, parallel computing, and computer visualization. Movies about the time evolution of matter (both dark and visible) in the universe will be made to allow the public to witness how simple physical principles can be used to reproduce the complex structures in the vast cosmos. The researchers will develop a new method, using numerical simulations and semi-analytical modeling, to reconstruct initial conditions from which the cosmic density field in the low-redshift universe has evolved; simulate the cosmic density field in both dark matter and gas using the reconstructed initial conditions; and study the relationship between galaxies, dark halos, dark matter, and the intergalactic medium to test theories of galaxy formation. The accuracy of this new method and its reliability will be quantified using detailed numerical simulations. Simulations will be run multiple times to explore cosmic variance. An output from this work will be a mock SDSS catalog, available to explore the comparison between observations and theory directly. The results of this research will provide insight into the processes that shape galaxies and large-scale structures, as well as the relationship between galaxies, and their environments and dark matter.