Day 1231

Friday.

1703.02991
The third data release of the Kilo-Degree Survey and associated data products
de Jong, et al

KiDS is an ongoing optical wide-fields making survey with the OmegaCAM camera at the VLT Survey Telescope.  It aims to image 1500 square degrees in four filters (ugri).  The core science driver is mapping the large-scale matter distribution in the Universe, using WL shear and photometric redshift measurements.  Further science cases include galaxy evolution, Milky Way structure, detection of high-redhisft clusters, and finding rare sources such as strong lenses and quasars.  Present DR3 and several associated data products, adding further area, homogenized photometric calibration, photometric redshifts and WL shear measurements to the first 2 releases.  A dedicated pipeline embedded in the Astro-WISE information system is used for the production of the main release.  Modifications with respect to earlier releases are described in detail.  Photometric redshifts have been derived using both Bayesian template fitting, and machine-learning techniques.  For the WL measurements, optimized procedures based on the THELI data reduction and lensfit shear measurement packages are used.  In DR3 stacked ugri images, weight maps, masks, and source lists for 292 new survey tiles (~300 sq. deg) are made available.  The multi-band catalogue, including homogenized photometry and photometric z, covers the combined DR1, DR2 and DR3 footprint of 440 survey tiles (447 sq.deg).  Limiting magnitudes are typically 24.3, 25.1, 24.9, 23.8 (5 sigma in a 2" aperture) in ugri, respectively, and the typical r-band PSF size is less than 0.7".  The photometric homogenization scheme ensures accurate colors and an absolute calibration stable to ~2% for gri's and ~3% in u.  Separately released are WL shear catalogue and photometric redshifts based on 2 different machine-linearing techniques.


1703.03383
KiDS-450: Tomographic cross-correlation of galaxy shear with {/it Planck} Lensing
Harnois-Dëraps, et al

Present the tomographic cross-correlation between galaxy lensing measured in KiDS-450 with overlapping lensing measurements with CMB, as detected by Planck 2015.  Compare joint probe measurement to the theoretical expectation for a flat LCDM cosmology, assuming the best-fitting cosmological parameters from the KiDS-450 cosmic shear and Planck CMB analyses.  Find that the results are consistent within 1 sigma with the KiDS-450 cosmology, with an amplitude re-scaling parameter A_KiDS=0.86±0.19.  Adopting a Planck cosmology, find the results are consistent within 2 sigma, with A_Planck =0.68±0.15.  Show that the agreement is improved in both cases when the contamination to the signal by intrinsic galaxy alignments is accounted for, increasing A by ~0.1.  This is the first topographic analysis of the galaxy  lensing -- CMB lensing crosscorrelation signal, and is based on 5 photometric redshift bins.  Use this measurement as an independent validation of the multiplicative shear calibration and of the calibrated source redshift distribution at high z.  Find that constraints on these 2 quantities are strongly correlated when obtained from this technique, which should therefore not be considered as a stand-alone competitive calibration tool.