The galaxy luminosity function and the redshift-distance controversy (A Review)

Area of Science:

• Astronomy and Astrophysics
• Cosmology

Background:

• The relationship between a galaxy's distance and its redshift is fundamental to understanding the universe's expansion.
• Comparing linear and quadratic distance-redshift laws requires careful consideration of observational selection effects.

Purpose of the Study:

• To investigate the observational evidence for the distance-redshift relation in galaxies.
• To determine whether a linear or quadratic law best describes this relationship.

Main Methods:

• Analysis of the galaxy luminosity function.
• Examination of galaxy luminosity distributions across different redshift ranges.
• Assessment of the luminosities of brightest galaxies in groups and clusters.
• Application of the Tully-Fisher correlation.

Main Results:

• The galaxy luminosity function was explicitly defined.
• Observational selection effects were analyzed for their impact on distance-redshift law comparisons.
• Evidence from galaxy luminosities, brightest cluster galaxies, and the Tully-Fisher relation consistently favored the linear law.

Conclusions:

• The linear distance-redshift law is strongly supported by multiple lines of observational evidence.
• The findings have implications for cosmological models and our understanding of cosmic expansion.