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Calibrating photometric redshifts with intensity mapping observations

2017; American Physical Society; Volume: 96; Issue: 4 Linguagem: Inglês

10.1103/physrevd.96.043515

2470-0037

David Alonso, Pedro G. Ferreira, M. J. Jarvis, Kavilan Moodley,

Astronomy and Astrophysical Research

Imaging surveys of galaxies will have a high number density and angular resolution yet a poor redshift precision. Intensity maps of neutral hydrogen will have accurate redshift resolution yet will not resolve individual sources. Using this complementarity, we show how the clustering redshifts approach proposed for spectroscopic surveys can also be used in combination with intensity mapping observations to calibrate the redshift distribution of galaxies in an imaging survey and, as a result, reduce uncertainties in photometric-redshift measurements. We show how the intensity mapping surveys to be carried out with the MeerKAT, HIRAX and SKA instruments can improve photometric-redshift uncertainties to well below the requirements of DES and LSST. The effectiveness of this method as a function of instrumental parameters, foreground subtraction and other potential systematic errors is discussed in detail.