Cosmological parameter constraints from galaxy-galaxy lensing with the Deep Lens Survey

  • Published : 2017.10.10

Abstract

The Deep Lens Survey (DLS), a precursor to the Large Synoptic Survey Telescope (LSST), is a 20 deg2 survey carried out with NOAO's Blanco and Mayalltelescopes. DLS is unique in its depth reaching down to ~27th mags in BVRz bands. This enables a broad redshift baseline and is optimal for investigating cosmological evolution of the large scale structure. Galaxy-galaxylensing is a powerful tool to estimate averaged matter distribution around lensgalaxies by measuring shape distortions of background galaxies. The signal from galaxy-galaxy lensing is sensitive not only to galaxy halo properties, but also to cosmological environment at large scales. In this study, we measure galaxy-galaxy lensing and galaxy clustering, which together put strong constraints on the cosmological parameters. We obtain significant galaxy-galaxy lensing signals out to ~20 Mpc while tightly controlling systematics. The B-mode signals are consistent with zero. Our lens-source flip test indicates that minimal systematic errors are present in DLS photometric redshifts. Shear calibration is performed using high-fidelity galaxy image simulations. We demonstrate that the overall shape of the galaxy-galaxy lensing signal is well described by the halo model comprised of central and non-central halo contributions. Finally, we present our preliminary constraints on the matter density and the normalization parameters.

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