The discussion revolves around the potential explanation of flat rotation curves in spiral galaxies through the concept of dynamical friction. Participants explore the implications of mass segregation in galaxy clusters and its relevance to the distribution of matter in individual spiral galaxies, considering both theoretical and observational aspects.
Participants express differing views on the applicability of dynamical friction to explain flat rotation curves, with some supporting the idea while others provide counterarguments related to mass segregation and star formation processes. The discussion remains unresolved with multiple competing perspectives.
Limitations include the dependence on definitions of mass segregation and the unresolved nature of the relationship between star formation rates and rotation curves. The discussion does not reach a consensus on the mechanisms involved.
So what is it that makes mass segregation possible in clusters of galaxies - is it because they are more massive and slow?stefan r said:The Sun does not show mass segregation. All the elements remain present at the Sun's surface. At a galaxy scale molecules of gas are moving much to quickly. Convection dominates.
The gradient of heavier elements toward the galactic core and in the disc can be explained by an increased rate of star formation. It all started out as the same mix of gas but in denser regions the mass has been recycled through stars multiple times.
Black holes should be segregating toward the core of the galaxy. Large stars segregate into the center of clusters.
Ranku said:Can the flat rotation curve in an individual spiral galaxy, whereby heavier matter is concentrated at the center and hydrogen and dark matter is diffused, be also explained by dynamical friction?
Yes, you're right, and furthermore the observed distribution of heavier elements isn't enough to account for the peak in galactic rotation curves.Stefan r said:the gradient of heavier elements toward the galactic core and in the disk can be explained by an increased rate of star formation.