Code of Conduct
Helene Courtois (University of Lyon France and University of Hawaii USA)
While massive amounts of observational data as well as high performance super-computing capacities are becoming the norm for cutting edge research, our knowledge of the matter distribution in the Universe (on the Million Light years scale) remains an open question.
The science of mapping the heavens has since antiquity been known as "cosmography". On earth, cartographers evolved from surface mapping (2D) to elevation maps (3D) to tectonic mapping with real-time motions (GPS). Cosmologists are just now making this last step. In 2013 a detailed cartography of galaxy motions in a volume reaching 1% of the observable universe was made public, thanks to the joint efforts of two international projects: CLUES and "Cosmic Flows".
We have recently produced a newest catalog of galaxy gravitational velocities: "Cosmic Flows-2", which approximately doubles the dynamically cartographied volume of the universe. I will present results obtained when this catalogue is used by the CLUES project: an endeavor to run cosmological numerical simulations that are constrained to reproduce the observed cosmography. The time evolution of these simulations provides a detailed window on the history of how the local universe assembled and formed. I will conclude by focusing on a special place : the Great Attractor - a gravitational sink in the local universe which is pulling towards it many galaxies (including us). A comparison between the dynamics in the observed universe and the simulated one, allows us to map the dark matter distribution and to test the standard theory of structure formation. Mapping the distribution and motions of galaxies attempts to answer some of the most basic questions in cosmology: where are we? where do we come from? where are we going? and "why" are we going there?
