Hierarchical Bayesian inference of galaxy redshift distributions from photometric surveys
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Accepted version
Author(s)
Leistedt, B
Mortlock, DJ
Peiris, HV
Type
Journal Article
Abstract
Accurately characterizing the redshift distributions of galaxies is essential for analysing deep photometric surveys and testing cosmological models. We present a technique to simultaneously infer redshift distributions and individual redshifts from photometric galaxy catalogues. Our model constructs a piecewise constant representation (effectively a histogram) of the distribution of galaxy types and redshifts, the parameters of which are efficiently inferred from noisy photometric flux measurements. This approach can be seen as a generalization of template-fitting photometric redshift methods and relies on a library of spectral templates to relate the photometric fluxes of individual galaxies to their redshifts. We illustrate this technique on simulated galaxy survey data, and demonstrate that it delivers correct posterior distributions on the underlying type and redshift distributions, as well as on the individual types and redshifts of galaxies. We show that even with uninformative priors, large photometric errors and parameter degeneracies, the redshift and type distributions can be recovered robustly thanks to the hierarchical nature of the model, which is not possible with common photometric redshift estimation techniques. As a result, redshift uncertainties can be fully propagated in cosmological analyses for the first time, fulfilling an essential requirement for the current and future generations of surveys.
Date Issued
2016-06-15
Online Publication Date
2016-06-15
2016-08-19T15:13:06Z
Date Acceptance
2016-05-27
ISSN
1365-2966
Publisher
Oxford University Press
Start Page
4258
End Page
4267
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
460
Issue
4
Copyright Statement
© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
Source Database
crossref
Sponsor
Science and Technology Facilities Council [2006-2012]
Grant Number
ST/K001051/1
Subjects
Astronomy & Astrophysics
0201 Astronomical And Space Sciences
Publication Status
Accepted