The Galaxy-Halo Connection Across Cosmic Time

Coordinators: Alexie Leauthaud, Risa Wechsler, and Andrew Zentner

Scientific Advisors: Carlos Frenk, Marla Geha, Andrey Kravtsov, Romain Teyssier, and Martin White

The formation of galaxies is still one of the key unsolved problems of astrophysics and cosmology. This is because the processes involved are complex, multi-scale, and are highly non-linear. At the same time, despite the apparent complexity of these processes, observed properties of galaxies exhibit a number of striking regularities,  including tight correlations between galaxy sizes, masses, luminosities, and dynamical properties. Moreover, there is a growing empirical evidence indicating that key properties of galaxies tightly correlate with properties of extended dark matter halos in which they form. Phenomenological modeling based on such empirical correlations unlocks the predictive power of large cosmological N-body simulations, enabling astrophysicists to infer the underlying dark matter distribution in the Universe and to exploit large-scale galaxy surveys as probes of cosmological physics.

The next generation of massive, wide-field surveys will observe billions of galaxies, including galaxies from the earliest epochs of their evolution. These surveys have the potential to transform our understanding of the evolution of structure in both the galaxy distribution and the dark matter distribution, and in so doing, to answer some of the most profound questions of galaxy formation and cosmology. However, maximizing the scientific impact of these forthcoming data sets depends upon bringing phenomenological models of the galaxy-dark matter halo connection to the next level of precision. This program aims to bring together experts in the statistics of the galaxy-halo connection, cosmologists, survey scientists, and observers and theorists working on galaxy evolution to foster discussions about observational probes of the galaxy-dark matter connection and to spur on the development of next-generation theoretical methods.  To brainstorm and generate ideas, we will hold a conference on the galaxy-halo connection and its role in the science of large cosmological surveys on May 15-19, 2017.