Phil Bull, UCB
Cosmological tests of gravity with radio telescopes
GR is astoundingly well-tested in the small-scale, weak-field limit, and constraints in the strong field limit are not far behind thanks to recent gravitational wave and binary pulsar observations. The cosmological regime remains a viable, well-motivated hiding place for possible deviations from GR though. I discuss how radio telescopes are particularly well-suited to the task of determining the nature of gravity on cosmological scales. As well as constraining background expansion at high redshift and providing new ways of measuring the weak lensing signal, radio surveys will be able to make the first practical measurements of clustering at the Hubble scale at late times. I will also describe several novel observational strategies that will make these measurements possible, and discuss how they can be supported experimentally.
1:10 pm (Cosmology/ BCCP)
Alexandra Amon, Edinburgh
Weak Lensing with the ESO Kilo-Degree Survey
The Kilo Degree Survey, (KiDS) is an ongoing weak lensing survey that will span 1500 square degrees, on completion, in nine optical-NIR bands. I will summarize the recent cosmology results from our analysis of the first third of the survey area, and detail an important test for the robustness of our weak lensing analysis, where I compare our fiducial high-quality KiDS multi-band dataset with 815 square degrees of the overlapping, shallower KiDS i-band-only survey. I will conclude by presenting a new test of General Relativity, measuring the "gravitational slip" statistic, E_G, in a joint analysis of KiDS with the same-sky spectroscopic surveys; BOSS and the recently completed 2dF Lensing Survey.