polytropes

Example:Isophotes can be contrasted with polycyclic models, which show varying properties in different directions.

Definition:Curves of equal brightness or flux density in an image, often used to describe the shape of galaxies without varying properties in different spatial directions.

Example:Isochores describe uniform regions, while polycyclic galaxies exhibit variability, making them distinct in galactic dynamics studies.

Definition:Steady regions where the properties (such as density or temperature) are the same throughout, unlike polycyclic galaxies which show variability in different directions.