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arXiv · 1512.00600

Reconstructing the galaxy redshift distribution from angular cross power spectra

L. Sun·H. Zhan·C. Tao
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Abstract

The control of photometric redshift (photo-$z$) errors is a crucial and challenging task for precision weak lensing cosmology. The spacial cross-correlations (equivalently, the angular cross power spectra) of galaxies between tomographic photo-$z$ bins are sensitive to the true redshift distribution $n_i(z)$ of each bin and hence can help calibrate the photo-$z$ error distribution for weak lensing surveys. Using Fisher matrix analysis, we investigate the contributions of various components of the angular power spectra to the constraints of $n_i(z)$ parameters and demonstrate the importance of the cross power spectra therein, especially when catastrophic photo-$z$ errors are present. We further study the feasibility of reconstructing $n_i(z)$ from galaxy angular power spectra using Markov Chain Monte Carlo estimation. Considering an LSST-like survey with $10$ photo-$z$ bins, we find that the underlying redshift distribution can be determined with a fractional precision ($σ(θ)/θ$ for parameter $θ$) of roughly $1\%$ and $10\%$ for the mean redshift and width of $n_i(z)$, respectively.

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L. Sun, H. Zhan, C. Tao. 2015-12-02. Reconstructing the galaxy redshift distribution from angular cross power spectra. https://arxiv.org/abs/1512.00600

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