Institute for Advanced Study Informal Astrophysics Seminar

The clustering of galaxies in ongoing and upcoming galaxy surveys contains a wealth of cosmological information. Extracting this information is a non-trivial task since galaxies and their host haloes are stochastic tracers of the non-linear matter density field. The relation between matter and halo distribution is commonly expressed in terms of a local bias model. Recent studies have revealed inconsistencies between the simple local Eulerian bias model and simulations. I will explain two effects that can explain and partially cure these inconsistencies. Firstly, non-local bias terms proportional to the tidal tensor are generated by gravitational evolution and their presence can be detected in the halo bispectrum. Secondly, I will explain how discreteness of haloes and their small scale exclusion alters the large scale halo power spectrum.