Galactic Spiral Structure

The reasons why galaxies take a spiral form has been something of a
mystery. The most popular model, Density Wave Theory,

http://en.wikipedia.org/wiki/Density_wave_theory

defies basic physical principles.

For some while I have been studying the distribution of velocities of
local stars. Recently it occurred to me that the observed velocity
distribution could be explained by a much simpler and more obvious model
of spiral structure, in which mutual gravity causes the orbits of stars
to align along spiral arms. Stars do not pass through the arms on near
circlar orbits, as in density wave theory, but follow the arm on
perturbed elliptical orbits, joining it just before apocentre and
leaving just after pericentre.

I have written this up in

http://arxiv.org/abs/0901.3503

In the paper, I have shown by both approximation and numerical
simulation that spirals are dynamically stable solutions of the many
body problem for galaxies, shown how flocculent and multiarmed spirals
evolve to grand-design two-armed, and explained the formation of bars
and rings.

By comparison with hydrogen maps and the observed stellar velocity
distribution, I have shown that the Milky Way is a grand design two
armed spiral, with a lower pitch angle than the usual four armed maps.


Regards

--
Charles Francis
moderator sci.physics.foundations.
charles (dot) e (dot) h (dot) francis (at) googlemail.com (remove spaces and
braces)

http://www.teleconnection.info/rqg/MainIndex