Perturbations and dark matter in galaxy clusters?
stargene
I am trying to better understand the collision of two clusters of
galaxies as reported in "Discovery of a ringlike dark matter
structure in the core of the galaxy structure CL0024+17 " by M.
J. Jee et al (found at arXiv:0705.2171v1 (15 May 2007). This
required some basic learning about clusters in general.
I've gotten confused over the following...
1) Different researchers/groups seem to view galaxy cluster
anatomy differently. Some say that perturbation or disturbance
of galaxies is more likely to happen when they pass through
the dense central regions of their clusters. Others say that
chances for disturbance are higher in the outskirts, due to
lower velocity of passage and thus more chance of two or
more galaxies interfering with one another (ie: more time)
and that indeed, galaxies in peripheral regions show more
signs of disturbance. Which is more correct?
2) I get the sense that the dark matter haloes of galaxy clusters
tend to be more concentrated toward their centers, with rela-
tively little dark matter on the outskirts. This leads to another
question: Do galaxies in the outskirts of clusters tend to show
LESS than the expected amount of dark matter for their generic
types elsewhere in the universe, as measured by, say their local
velocity curves, dispersions &/or gravitational lensing?
Where might I find out more on these specific issues? I've had
little luck simply using keywords at the Harvard ADS site.
Thanks,
Gene