Determination of \Omega_\Lambda and H_0 from photometric data of radio galaxies

TL;DR

This study uses photometric data of elliptical galaxies, including radio galaxies, to estimate cosmological parameters H_0 and Omega_Lambda by analyzing the redshift-age relationship of stellar systems, providing model-dependent bounds.

Contribution

It introduces a method to determine H_0 and Omega_Lambda from galaxy ages independent of other cosmological models, using synthetic spectra evolution models.

Findings

Estimated H_0 as 72±10 km/s/Mpc with GISSEL model.

Estimated H_0 as 53±10 km/s/Mpc with PEGASE model.

Determined Omega_Lambda as approximately 0.8 in both models.

Abstract

From photometric observations of elliptical galaxies, among which are both radio galaxies and radio-quiet objects, an investigation was carried out of the relationship `redshift -- age of the stellar system' $(\Delta z/\Delta t)$. By means of this relationship cosmological parameters $H(z)$ and $\Omega_\Lambda$ are estimated. Ages of stellar systems are determined within the framework of evolution models of synthetic spectra PEGASE and GISSEL. This approach can be considered as time study of objects of the early Universe independent of other cosmological models. Construction of a pooled sample is described, containing 220 objects from different populations of elliptical galaxies, for which an analysis of the upper limit of the age of formation of a stellar system was performed. These data were used to estimate the boundaries of determination of the cosmological parameters $H_0$ and $\Lambda$--term: $H_0=72\pm10$ and $\Omega_\Lambda=0.8\pm0.1$ in the model GISSEL and $H_0=53\pm10$, and $\Omega_\Lambda=0.8\pm0.1$ in the model PEGASE.