Cross-correlating spectroscopic and photometric galaxy surveys

Martin B. Eriksen, Enrique Gaztañaga

    Research output: Contribution to journalArticleResearchpeer-review


    © International Astronomical Union 2015. Does photometric and spectroscopic survey benefit from overlapping areas? The photometric survey measures 2D Weak Lensing (WL) information from galaxy shape distortions. On the other hand, the higher redshift precision of an spectroscopic survey allows measurements of redshift space distortions (RSD) and baryonic accustic oscillations (BAO) from 3D galaxy counts. The two surveys are combined using 2D-correlations, using sufficiently narrow bins to capture the radial information. This poster present effects of RSD and intrinsic correlations between narrow redshift bins. In understanding how the effects affects cosmological constrains, we first define two stage-IV and then present forecast for various configurations. When surveys overlap, they benefit from additional cross-correlations and sample variance cancellations from overlapping volumes. For a combined dark energy and growth history figure of merit, the result increase 50% for overlapping surveys, corresponding to 30% larger area.
    Original languageEnglish
    Pages (from-to)213-215
    JournalProceedings of the International Astronomical Union
    Publication statusPublished - 1 Jan 2015


    • galaxies: distances and redshifts
    • techniques: spectroscopic surveys


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