Calibrating photometric redshifts with intensity mapping observations
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
American Physical Society
Abstract
Imaging surveys of galaxies will have a high number density and angular resolution yet a poor
redshift precision. Intensity maps of neutral hydrogen (HI) 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.
Description
Keywords
Photometric redshifts, Intensity mapping, Galaxies, MeerKAT, HIRAX, SKA
Citation
Alonso, D. et al. (2017). Calibrating photometric redshifts with intensity mapping observations. Physical Review D, 96: 043515