Determination of the Hubble Constant Using Cepheids

TL;DR

This paper presents a statistical method using Cepheid variables to accurately determine the Hubble constant, achieving a range of 66 to 80 km/s/Mpc with high correlation to existing data.

Contribution

Introduces a Gaussian fitting approach for Cepheid data to improve distance measurements and Hubble constant estimation.

Findings

Derived H0 range of 66-80 km/s/Mpc with +/- 5 km/s/Mpc accuracy.

Achieved 99.68% correlation between computed and published distance moduli.

Validated method reliability through high correlation with literature data.

Abstract

This paper introduces a statistical treatment to use Cepheid variable stars as distance indicators. The expansion rate of the Universe is also studied here through deriving the value of the Hubble constant H0. A Gaussian function approximation is proposed to fit the absolute magnitude and period of Cepheid variables in our galaxy. The calculations are carried out on samples of Cepheids observed in 23 galaxies to derive the distance modulus (DM) of these galaxies based on the frequency distributions of their periods and intrinsic apparent magnitudes. The DM is the difference between the apparent magnitude for extragalactic Cepheids and the absolute magnitude of the galactic Cepheids at maximum number. It is calculated by using the comparison of the period distribution of Cepheids in our galaxy and in other galaxies. This method is preferred due to its simplicity to use and its efficiency in providing reliable DM. A linear fit with correlation coefficient of 99.68% has been found between the published distance modulus and that computed one in the present work. From the present sample, a value of H0 in the range of 66 to 80 +/- 5 km/s Mpc is determined. The present procedure of computation and its accuracy are confirmed by the high correlation found between our computed DM and that published in the literature.