Thursday, April 13, 2006

Intrinsic alignments & Lots 'o talks

Intrinsic Alignments

Finished a measurement of intrinsic alignments
in clusters. Used Berlind's spectroscopic clusters
sample cross correlated with the main sample. I'm
getting a fairly weak bound (no detection), but this is
the first such measurement in clusters that I know of.

This shear needs to be converted to "delta sigma" as
measured for the clusters and I have done this.


Lots of talks here this week. Two 1.5 hour talks by
Leonard Susskind and a talk by Roger Penrose, plus
a job talk by Andrew Zentner and Alice Shapley is
talking tomorrow.

Susskind and Penrose both talked about things we
don't understand. Susskind discussed, for example,
how everyone loves the eternal inflation, bubble
nucleation, pocket universe theory, but at this point
its just a neat idea with no conceptual or mathematical
foundation. He tried to show that there are indications
that there might exist such a foundation.

Penrose talked about what happened before the big bang.
All the math breaks down there both classically and
the best quantum efforts, so you have to come up with
something new. His talk centered around the concept
that, at a nearly infinite time from now when lambda has
accelerated everything away and if all particles have decayed
away and black holes have evaporated, and somehow you
could get rid of electrons too, then there would be only
photons in the universe. In that case time has no meaning
at all since photons don't experience times. You can't build
clocks. This is an interesting idea. But then he made a huge
leap and said that if suddenly the phase space is rescaled so that
it appears to be a very dense universe, then it looks
like the big bang and everything starts over again.


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