The Reliability of Redshift Values in Determination of Structures in the Universe

In order to characterize the structures in the universe, The CFHTLS Wide 4 (W4) field data of the T0007 version of the photometric color catalog generated from observations made by Terapix with the filters of the Megacam camera of CFHTLS and the images of Wide 4, W4 were used. In order to control the photometric red shift values obtained with the spectroscopic red shift values, the VIPERS catalog obtained by the spectroscopic method for the CFHTLS W4 field was taken. The results of the studies for the ranges of 0.2 ≤ z ≤ 1.5 and 17.5 ≤ i'AB ≤ 21.5 of the redwood deposit were found to have a catastrophic error of 8.5% and an accuracy value of 0.031. As a result of the investigation based on selected galaxy SEDs for analysis, the catastrophic error of elliptic galaxies, which is quite different from the Milky Way Galaxy in 17.5 ≤ i'AB ≤ 24, is determined as 4.1% and the accuracy value is 0.030; the best correlation coefficient belongs to elliptical galaxies (r = 0.929). The relationship between the photometric and spectroscopic redshift values obtained for elliptical galaxies was determined as zp = (0.953 ± 0.008) zs + (0.083 ± 0.014).

Anahtar Kelimeler: Photometric redshift, large scale structure, galaxies, CFHTLS

In order to characterize the structures in the universe, The CFHTLS Wide 4 (W4) field data of the T0007 version of the photometric color catalog generated from observations made by Terapix with the filters of the Megacam camera of CFHTLS and the images of Wide 4, W4 were used. In order to control the photometric red shift values obtained with the spectroscopic red shift values, the VIPERS catalog obtained by the spectroscopic method for the CFHTLS W4 field was taken. The results of the studies for the ranges of 0.2 ≤ z ≤ 1.5 and 17.5 ≤ i'AB ≤ 21.5 of the redwood deposit were found to have a catastrophic error of 8.5% and an accuracy value of 0.031. As a result of the investigation based on selected galaxy SEDs for analysis, the catastrophic error of elliptic galaxies, which is quite different from the Milky Way Galaxy in 17.5 ≤ i'AB ≤ 24, is determined as 4.1% and the accuracy value is 0.030; the best correlation coefficient belongs to elliptical galaxies (r = 0.929). The relationship between the photometric and spectroscopic redshift values obtained for elliptical galaxies was determined as zp = (0.953 ± 0.008) zs + (0.083 ± 0.014).

Keywords: Photometric redshift, large scale structure, galaxies, CFHTLS

İğdi Şen, M. (2018). The Reliability of Redshift Values in Determination of Structures in the Universe. Journal of Current Researches on Engineering, Science and Technology, 4 (1), 69-80.