Cosmological observational tests in the JWST Era I: angular size - redshift
Published: 07/2025
Evolution of galaxy linear sizes (effective diameters) in the ΛCDM model, statistics for 50 redshift bins. Points show the mean galaxy sizes in each bin with their standard errors of the mean (grey points denote bins excluded due to low redshift or insufficient number of objects). Lines indicate the best-fit curves; shaded areas show the 3σ formal fitting uncertainty. Top: spectroscopic redshifts, bottom: photometric redshifts.
Raikov A. A.; Tsymbal V. V.; Lovyagin N. Yu.
This study is denoted to the cosmological "angular size - redshift" test. An analysis is performed of the angular and linear sizes of galaxies from the new ASTRODEEP-JWST catalogue, which contains over 500,000 objects at high redshifts (up to ~20 photometrically determined and up to ~14 spectroscopically determined). For the calculations, 6 860 galaxies with reliably determined spectroscopic redshifts and 319,771 galaxies with known photometric redshifts were used. The linear sizes of galaxies were computed within the framework of two cosmological models - the standard (ΛCDM) model and one of the static models (the so-called "tired light" model). We shown that within the framework of the ΛCDM model, a significant evolution of the linear sizes of galaxies is observed, with the rate of the evolution closely matching the rate of the cosmic expansion. In contrast, in the static model, the characteristic linear sizes of a galaxies exhibit almost no evolution with increasing z.