Calibrating photometric redshift distributions with cross-correlations

Understand

The next generation of proposed galaxy surveys will increase the number of galaxies with photometric redshifts by two orders of magnitude, drastically expanding both redshift range and detection threshold from the current state of the art.

• Obtaining spectra for a fair sub-sample of this new data could be cumbersome and expensive.
• However, adequate calibration of the true redshift distribution of galaxies is vital to tapping the potential of these surveys.
• We examine a promising alternative to direct spectroscopic follow up: calibration of the redshift distribution of photometric galaxies via cross-correlation with an overlapping spectroscopic survey whose members trace the same density field.