Calibrating photometric redshifts with intensity mapping observations
Date
2017Author
Alonso, David
Ferreira, Pedro G.
Jarvis, Matt
Moodley, Kavilan
Metadata
Show full item recordAbstract
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.