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Star/galaxy separation at faint magnitudes : application to a simulated Dark Energy Survey

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Star/galaxy separation at faint magnitudes : application to a simulated Dark Energy Survey

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Título Star/galaxy separation at faint magnitudes : application to a simulated Dark Energy Survey
Autor Soumagnac, Maayane Tamar
Abdalla, Filipe B.
Lahav, Ofer
Kirk, Donnacha
Sevilla Noarbe, Ignacio
Bertin, Emmanuel
Rowe, Barnaby T. P.
Annis, James T.
Busha, M. T.
Costa, Luiz N. da
Frieman, Joshua A.
Gaztañaga, Enrique
Jarvis, Michael
Lin, H.
Percival, Will J.
Santiago, Basilio Xavier
Sabiu, Cristiano Giovanni
Wechsler, Risa H.
Wolz, Laura
Yanny, Brian
Abstract We address the problem of separating stars from galaxies in future large photometric surveys. We focus our analysis on simulations of the Dark Energy Survey (DES). In the first part of the paper, we derive the science requirements on star/galaxy separation, for measurement of the cosmological parameters with the gravitational weak lensing and large-scale structure probes. These requirements are dictated by the need to control both the statistical and systematic errors on the cosmological parameters, and by point spread function calibration. We formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier. In order to achieve these requirements at faint magnitudes, we propose a new method for star/galaxy separation in the second part of the paper.We first use principal component analysis to outline the correlations between the objects parameters and extract from it the most relevant information.We then use the reduced set of parameters as input to an Artificial Neural Network. This multiparameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SEXTRACTOR), especially at faint magnitudes: it increases the purity by up to 20 per cent for stars and by up to 12 per cent for galaxies, at i-magnitude fainter than 23.
Contido em Monthly notices of the Royal Astronomical Society. Oxford. Vol. 450, no. 1 (June 2015), p. 666-680
Assunto Cosmologia
Energia escura
Galaxias
Lentes gravitacionais
Mapeamentos astronômicos
[en] Cosmology: observations
[en] Dark energy
[en] Gravitational lensing: weak
[en] Large
[en] Methods: data analysis
[en] Scale structure of universe
[en] Surveys
Origem Estrangeiro
Tipo Artigo de periódico
URI http://hdl.handle.net/10183/126984
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