Galaxy-Galaxy lensing in HSC: Validation tests and the impact of heterogeneous spectroscopic training sets

Citation:

Speagle JS, Leauthaud A, Huang S, Bradshaw CP, Ardila F, Capak PL, Eisenstein DJ, Masters DC, Mandelbaum R, More S, et al. Galaxy-Galaxy lensing in HSC: Validation tests and the impact of heterogeneous spectroscopic training sets. Monthly Notices of the Royal Astronomical Society [Internet]. 2019;490 :5658-5677.

Date Published:

December 01, 201

Abstract:

Although photometric redshifts (photo-z's) are crucial ingredients forcurrent and upcoming large-scale surveys, the high-quality spectroscopicredshifts currently available to train, validate, and test them aresubstantially non-representative in both magnitude and colour. Weinvestigate the nature and structure of this bias by tracking howobjects from a heterogeneous training sample contribute to photo-zpredictions as a function of magnitude and colour, and illustrate thatthe underlying redshift distribution at fixed colour can evolve stronglyas a function of magnitude. We then test the robustness of the galaxy-galaxy lensing signal in 120 deg2 of HSC-SSP DR1 data tospectroscopic completeness and photo-z biases, and find that theirimpacts are sub-dominant to current statistical uncertainties. Ourmethodology provides a framework to investigate how spectroscopicincompleteness can impact photo-z-based weak lensing predictions infuture surveys such as LSST and WFIRST.

Website