On the complementarity of galaxy clustering with cosmic shear and flux
  magnification
  In this paper, we motivate the use of galaxy clustering measurements using
photometric redshift information, including a contribution from flux
magnification, as a probe of cosmology. We present cosmological forecasts when
clustering data alone is used, and when clustering is combined with a cosmic
shear analysis. We consider two types of clustering analysis: firstly,
clustering with only redshift auto-correlations in tomographic redshift bins;
secondly, using all available redshift bin correlations. Finally, we consider
how inferred cosmological parameters may be biased using each analysis when
flux magnification is neglected. Results are presented for a Stage III
ground-based survey, and a Stage IV space-based survey modelled with
photometric redshift errors, and values for the slope of the luminosity
function inferred from CFHTLenS catalogues. We find that combining clustering
information with shear can improve constraints on cosmological parameters,
giving an improvement to a Dark Energy Task Force-like figure of merit by a
factor of 1.33 when only auto-correlations in redshift are used for the
clustering analysis, rising to 1.52 when cross-correlations in redshift are
also included. The addition of galaxy-galaxy lensing gives further improvement,
with increases in figure of merit by a factor of 2.82 and 3.7 for each type of
clustering analysis respectively. The presence of flux magnification in a
clustering analysis does not significantly affect the precision of cosmological
constraints when combined with cosmic shear and galaxy-galaxy lensing. However
if magnification is neglected, inferred cosmological parameter values are
biased, with biases in some cosmological parameters larger than statistical
errors. (Abridged)
