Weak-lensing study in VOICE survey - I. Shear measurement

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Miniatura
Fecha
2018-09
Profesor/a Guía
Facultad/escuela
Idioma
en
Título de la revista
ISSN de la revista
Título del volumen
Editor
Oxford University Press
Nombre de Curso
Licencia CC
Licencia CC
Resumen
The VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey is a Guaranteed Time programme carried out with the European Southern Observatory (ESO) VLT Survey Telescope (VST) telescope to provide deep optical imaging over two 4 deg2 patches of the sky centred on the Chandra Deep Field South (CDFS) and ES1 as part of the ESO-Spitzer Imaging Extragalactic Survey. We present the cosmic shear measurement over the 4 deg2 covering the CDFS region in the r band using LensFit. Each of the four tiles of 1 deg2 has more than 100 exposures, of which more than 50 exposures passed a series of image quality selection criteria for weak-lensing study. The 5σ limiting magnitude in r band is 26.1 for point sources, which is ≳1 mag deeper than other weak-lensing survey in the literature [e.g. the Kilo Degree Survey (KiDS) at VST]. The photometric redshifts are estimated using the VOICE u, g, r, i together with near-infrared VIDEO data Y, J, H, Ks. The mean redshift of the shear catalogue is 0.87, considering the shear weight. The effective galaxy number density is 16.35 gal arcmin-2, which is nearly twice the one of KiDS. The performance of LensFit on such a deep data set was calibrated using VOICE-like mock image simulations. Furthermore, we have analysed the reliability of the shear catalogue by calculating the star-galaxy crosscorrelations, the tomographic shear correlations of two redshift bins and the contaminations of the blended galaxies. As a further sanity check, we have constrained cosmological parameters by exploring the parameter space with Population Monte Carlo sampling. For a flat Λ cold dark matter model, we have obtained Σ8 = σ8(Ωm/0.3)0.5 = 0.68+0.11 -0.15. © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
Notas
Indexación: Scopus.
We thank Jun Zhang for helpful comments on shear measurement. LPF acknowledges the support from NSFC grants 11673018, 11722326 & 11333001; STCSM grant 16ZR1424800 & 188014066; and SHNU grant DYL201603. ZHF acknowledges the support from NSFC grants 11333001 and 11653001. XKL acknowledges the support from YNU grant KC1710708 and General Financial grant from China Postdoctoral Science Foundation with grant no. 2016M591006. Support for GP is provided by the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. MR acknowledges the support from PRIN MIUR 2015 ‘Cosmology and Fundamental Physics: illuminating the Dark Universe with Euclid’. MV acknowledges support from the European Commission Research Executive Agency (FP7-SPACE-2013-1 GA 607254), the South African Department of Science and Technology (DST/CON 0134/2014), and the Italian Ministry for Foreign Affairs and International Cooperation (PGR GA ZA14GR02).
Palabras clave
Cosmology: observations, Gravitational lensing: weak, Methods: data analysis, Surveys
Citación
Monthly Notices of the Royal Astronomical Society, 479(3), pp. 3858-3872.
DOI
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