"Joseph Lazio" wrote...
in message ...

"P" == Painius writes:

P So in addition to the dark matter believed to be a significant part
P of galaxies, there appear to be profound concentrations of dark
P matter associated with the center of galaxy clusters as well.

P Perhaps we can train the powerful Hubble on the central area of our
P Local Cluster? Maybe there are distant galaxies that will be
P distorted by the gravitational lensing of dark matter at our own
P galaxy cluster's center?

The problem is that we are not in a "real" cluster. We are in a small
group of galaxies, composed of the Milky Way, the Andromeda Galaxy,
M33, and various dwarfs. The total mass of this group is perhaps 100
times smaller than the typical large cluster from which gravitational
lensing is seen. Moreover, we are sitting in the middle of it.

Thanks, Joseph... not sure how you come by that we're in the middle
of the LG. The following, while depicting us in the center, actually
shows that the grouping is quite off-center. For the most part, the
center appears to be off to the right and down from our galaxy...

http://www.anzwers.org/free/universe/localgr.html

If we zoom out x20 from the above link...

http://www.anzwers.org/free/universe/virgo.html

....we find that our Local (non)Cluster is pretty much on the outskirts
of the gigantic Virgo Supercluster of galaxy groups.

The nearest cluster of any reasonable heft is the Virgo Cluster. I'm
not sure if anybody's ever looked for gravitational lensing from it,
but ADS or astro-ph will likely contain a reference if so.

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Could not find anything in ADS, but astro-ph is working on it...

http://xxx.soton.ac.uk/abs/astro-ph/0003422

So Joseph, the nature of centro-cluster dark matter leans me
toward lots of rogue black holes circulating along with the
galaxies. Probably lots of activity and collisions. We may be
very fortunate to be in the outskirts!

happy days and...
starry starry nights!

--
Our heads up in the sky,
We're so clueless of our worth...
Whose sky no longer shines
As we lose our Mother-Earth?

As people we must learn
About the care of planet parts,
To leave the world a better turn--
Empower brand new hearts!

Paine Ellsworth