Princeton University

Measuring and Modelling Redshift-space Distortions in the Galaxy Distribution

John Peacock
University of Edinburgh
March 3, 2015

Deviations from a uniformly expanding universe are of interest in modern cosmology, most particularly because the amplitude of such peculiar motions measures the strength of gravity on scales of roughly 10-100 Mpc. I will review various recent attempts to measure these velocity effects in leading galaxy surveys, together with new rapid approximate means of generating the simulated universes that are needed in order to extract validated results from the data.

Level raising mod 2 and arbitrary 2-Selmer ranks

Chao Li
Harvard University
December 4, 2014
We prove a level raising mod $p = 2$ theorem for elliptic curves over $\mathbb Q$, generalizing theorems of Ribet and Diamond-Taylor. As an application, we show that the 2-Selmer rank can be arbitrary in level raising families. We will begin by explaining our motivation from W. Zhang's approach to the $p$-part of the BSD conjecture. Explicit examples will be given to illustrate different phenomena compared to odd $p$. This is joint work with Bao V. Le Hung.