Day 1287

Friday.


1707.04105
KiDS-i-800: comparing weak gravitational lensing measurements in same-sky surveys
Amon, et al

Present a weak gravitational lensing analysis of 815 deg2 of i-band imaging from KiDS-i-800.  In contrast to the deep r-band observations, which take priority during excellent seeing conditions and form the primary KiDS dataset (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 the analysis, introduce two new 'null' tests.  The 'nulled' 2pt shear correlation function uses a matched catalogue to show that KiDS-i-800 and KiDS-r-450 shear calibration agree at the level of 1±4%.  Use 5 galaxy lens samples to determine a 'nulled' gg-lensing signal from the full KiDS-i-800 and KiDS-r-450 surveys and find that the measurements agree to 7±5% when the KiDS-i-800 source redshift distribution is calibrated using 30-band photometric redshifts from the COSMOS survey.  With an average effective source density of 3.8 galaxies/arcmin^2, a median redshift of z_med~0.5 and complete spectroscopic overlap, the wide area KiDS-i-band imaging is ideal for large-area cross correlation studies.