Dr. Hendrik Hildebrandt

Argelander-Institut für Astronomie, Bonn

KiDS+VIKING: Improved cosmological constraints from cosmic shear tomography with optical+infrared data

Abstract:

Cosmic shear tomography yields cosmological insights complementary to other probes like the cosmic microwave background (CMB). Ongoing wide-field imaging surveys exploit this to come up with competitive constraints on important cosmological parameters like the matter density and the amplitude of the matter power spectrum. In this talk I will concentrate on recent results from the ongoing European KiDS (Kilo Degree Survey) and VIKING (VISTA Kilo Degree Infrared Galaxy Survey) projects. This unique combination of an optical and an infrared imaging survey over hundreds of square degrees on the sky allows us to reach an unprecedented accuracy in the redshift calibration of the sources used in the weak lensing measurement. In combination with the well-calibrated KiDS shape measurements this will reveal whether the recently reported tension between Planck CMB measurements and KiDS optical-only cosmic shear results (Hildebrandt et al. 2017) still holds in this improved analysis.

Location: 31 Fitzwilliam Place, Dublin 2

Upcoming seminars:
https://www.dias.ie/2018/03/07/astronomy-and-astrophysics-seminar-schedule-2018/