KiDS-i-800: comparing weak gravitational lensing measurements from same-sky surveys
Abstract
We present a weak gravitational lensing analysis of 815 deg2 of i-band imaging from the Kilo-Degree Survey (KiDS-i-800). In contrast to the deep r-band observations, which take priority during excellent seeing conditions and form the primary KiDS data set (KiDS-r-450), the complementary yet shallower KiDS-i-800 spans a wide range of observing conditions. The overlapping KiDS-i-800 and KiDS-r-450 imaging therefore provides a unique opportunity to assess the robustness of weak lensing measurements. In our analysis we introduce two new `null' tests. The `nulled' two-point shear correlation function uses a matched catalogue to show that the calibrated KiDS-i-800 and KiDS-r-450 shear measurements agree at the level of 1 ± 4 per cent. We use five galaxy lens samples to determine a `nulled' galaxy-galaxy lensing signal from the full KiDS-i-800 and KiDS-r-450 surveys and find that the measurements agree to 7 ± 5 per cent when the KiDS-i-800 source redshift distribution is calibrated using either spectroscopic redshifts, or the 30-band photometric redshifts from the COSMOS survey.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2018
- DOI:
- 10.1093/mnras/sty859
- arXiv:
- arXiv:1707.04105
- Bibcode:
- 2018MNRAS.477.4285A
- Keywords:
-
- gravitational lensing: weak;
- surveys;
- galaxies: photometry;
- cosmology: observations;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 24 pages, 20 figures. Submitted to MNRAS. Comments welcome