Cosmology Seminar
Tue, October 03, 2017
1:10 pm (Cosmology/ BCCP)
Alexandra Amon, Edinburgh
Campbell 131
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.
Cosmology Seminar
Tue, September 26, 2017
1:10 pm (Cosmology/ BCCP)
Andrina Nicola, ETH Zurich
Campbell 131
Integrated approach to cosmology
Recent progress in observational cosmology and the establishment of ΛCDM have relied on the combination of different cosmological probes. These probes are not independent, since they all measure the same physical fields. The resulting cross-correlations allow for a robust test of the cosmological model through the consistency of different physical tracers and for the identification of systematics. Integrated analyses taking into account both the auto- as well as the cross-correlations between cosmological probes therefore present a promising analysis method for both current as well as future data.
In this talk, I will present an integrated analysis of CMB temperature anisotropies, CMB lensing, galaxy clustering and weak lensing as well as background probes. I will describe the cosmological probe combination framework, the obtained results and illustrate how this analysis has provided a confirmation of ΛCDM through the consistency of different probes. Furthermore, I will discuss possible tensions between the derived constraints on cosmological parameters and existing ones.
Cosmology Seminar
Tue, September 19, 2017
1:10 pm (Cosmology/ BCCP)
Julien Carron, Sussex
Campbell 131
Planck CMB delensing and beyond
The deflection of CMB photons by large-scale structures smooths the observed CMB acoustic peaks and introduces a sizeable white noise component in the polarization B-mode. In order to achieve best constraints on the inflationary perturbations tensor to scalar ratio, upcoming low-noise polarization-based experiments must be able to undo these deflections, an operation called delensing. I will present the first detection of B-mode delensing, and first internal delensing of the CMB that we recently performed on Planck public maps, as well as discuss methods and prospects for the future.