2 research outputs found
Transitioning from Stage-III to Stage-IV: cosmology from galaxy×CMB lensing and shear×CMB lensing
Transitioning from Stage-III to Stage-IV: cosmology from galaxy×CMB lensing and shear×CMB lensing
We examine the cosmological constraining power from two cross-correlation
probes between galaxy and CMB surveys: the cross-correlation of lens galaxy
density with CMB lensing convergence , and source
galaxy weak lensing shear with CMB lensing convergence
. These two cross-correlation probes provide an
independent cross-check of other large-scale structure constraints and are
insensitive to galaxy-only or CMB-only systematic effects. In addition, when
combined with other large-scale structure probes, the cross-correlations can
break degeneracies in cosmological and nuisance parameters, improving both the
precision and robustness of the analysis. In this work, we study how the
constraining power of
changes from Stage-III (ongoing) to Stage-IV (future) surveys. Given the
flexibility in selecting the lens galaxy sample, we also explore systematically
the impact on cosmological constraints when we vary the redshift range and
magnitude limit of the lens galaxies using mock galaxy catalogs. We find that
in our setup, the contribution to cosmological constraints from
and are comparable in
the Stage-III datasets; but in Stage-IV surveys, the noise in
becomes subdominant to cosmic variance, preventing
to further improve the constraints. This implies
that to maximize the cosmological constraints from future
analyses, we should
focus more on the requirements on instead of
. Furthermore, the selection of the lens sample
should be optimized in terms of our ability to characterize its redshift or
galaxy bias instead of its number density.Comment: 18 pages, 13 figure