Inner ring structures in galaxies as distance indicators. I - Dimensionless systematics of inner rings
Abstract
The statistical properties of the inner ring and broken ring structures observed in lenticular and spiral galaxies are investigated in relation to galaxy classification, structure and absolute magnitude as a basis for the use of the rings as distance indicators. Analyses of the relative frequencies of ring structures in galaxies of different morphological families and stages along the revised Hubble sequence are presented which demonstrate the importance of selection effects due to apparent diameter and inclination, and it is shown that for a sample of over 500 RC2 spirals with large diameters and favorable inclinations, pure inner rings are not common among the barred spirals and least common among the unbarred spirals. Comparison of the axial ratios of the ring and parent galaxy indicates that the rings are flat structures in the galactic plane, and may be intrinsically elongated in barred spiral galaxies. Finally, statistical analyses of the ratios of the isophotal and metric galaxy diameters to the ring diameters reveal the ratios to depend strongly on spiral galaxy type and family, and weakly on variety and luminosity class.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- December 1980
- DOI:
- 10.1086/190700
- Bibcode:
- 1980ApJS...44..451D
- Keywords:
-
- Distance;
- Galactic Structure;
- Ring Structures;
- Diameters;
- Lenticular Bodies;
- Spiral Galaxies;
- Astrophysics