Revisiting the Scale Length-mu0 Plane and the Freeman Law in the Local Universe

TL;DR

This study analyzes a large sample of local bright disk galaxies to examine the relationships between disk scale length, central surface brightness, and galaxy morphology, reaffirming the Freeman Law and providing new statistical insights.

Contribution

It offers the largest volume-corrected analysis to date of the scale length-mu0 relation and Freeman Law in the local universe, with implications for galaxy formation theories.

Findings

Late type spirals have lower surface brightness and larger scale lengths.

Freeman Law sets an upper limit for central surface brightness in bright galaxies.

Disks in late type spirals are systematically fainter in central brightness.

Abstract

We have used Virtual Observatory technology to analyse the disk scale length and central surface brightness for a sample of 29955 bright disk galaxies from the Sloan Digital Sky Survey. We use the results in the r-band and revisit the relation between these parameters and the galaxy morphology, and find the average disk surface brightness of 20.2(0.7) mag/arcsec^2. We confirm that late type spirals populate the lower left corner of the scale length-mu0 plane and that the early and intermediate spirals are mixed in this diagram, with disky ellipticals at the top left corner. We further investigate the Freeman Law and affirm that it indeed defines an upper limit for the disk central surface brightness in bright galaxies, and that disks in late type spirals have fainter central surface brightness. Our results are based on a volume corrected sample of galaxies in the local universe (z < 0.3) that is two orders of magnitudes larger than any sample previously studied, and deliver statistically significant implications that provide a comprehensive test bed for future theoretical studies and numerical simulations of galaxy formation and evolution.