The Shear Study Of Different Galaxies Types Based On VOICE

The VOICE survey is a project implemented by the "VLT Survey Telescope"(VST)European Southern Observatory(ESO)in Parana(Chile)with deep space optical imaging of the fields of CDFS and ES1,in which the CDFS area provides four bands of ugri optical imaging.This paper will study cosmic shear by using the data in VOICE covering the CDFS field,mainly based on observations of r-band.VOICE-CDFS consists of four areas of about 1 deg2 each.The average number of exposures per area exceeds 100 times,and more than 50 exposures have passed a series of selection criteria for the study of weak gravitational lensing.In addition,the observation depth of source is r ? 26.1 mag(within 5?),which is more than 1 mag deeper than the observation depth of the weak lensing survey project(such as Ki DS)in other literatures.The estimation of the photometric redshift of VOICE in the ugri band is performed together with VIDEO's Y,J,H,and Ks band data.After processing,the weighted average redshift in VOICE catalog is about 0.87,and the number density of the galaxy is about 17.05 /arcmin2 and it is about twice that of the Ki DS survey.In this paper,the shear catalog obtained from Lens Fit processing is to perform cosmic shear measurements,and the method classify galaxies is used by BPZ classification method.Then,we study cosmic shear two-point correlation functions and "galaxy-galaxy" lens signals on different types of VOICE galaxy samples.I analyzed the two-point cosmic shear function of the VOICE before classification,and found that the E/B mode signal can be clearly decomposed.The E mode signal shows a clear mass distribution in the target area,and B-mode signal which reflects systematic error tends to zero.However,because of the very small number of different sample of VOICE,especially of Elliptical,Spiral and Irregular sample,the E-mode signals of their aperture mass parameter <M2ap> are weak and the error bar is large on a small scale,and the B-mode signals also reflect the large systematic error of different galaxy catalog.For comparison,the shear catalogs of the six sky regions in Ki DS-450 are used to classify the galaxies and calculate the two-point correlation function of the shear,respectively,and have relatively good E/B signals.In the end,I study "galaxy-galaxy" lensing then measured and got better ESD signals---??(R)from galaxy samples of different type samples of VOICE for exploring the dark matter halo environment in the VOICE-CDFS area.