From: Henk Hoekstra (hoekstra@uvic.ca)
Date: Thu Jan 26 2006 - 14:34:51 PST
Hi Saul et al.,
I have been looking at the proposal pdf file on the website (not sure
this is the right place), but I am wondering whether we should start
the proposal differently, highlighting the NEW things we can do with
the cycle 15 observations.
The way it reads now it's more of the same (everybody wants more data...)
and only later on it becomes clear we want to do all kinds of new things.
I noticed the weak lensing has been cut considerably, but I think
we should be careful not to compress it too much. For instance, my
feeling is that the strong lensing part is too long. So far the
strong lensing hasn't been overwhelming, and I am not sure it will
ever be... these are high-z clusters after all. I don't think the
sample of clusters studied here will really advance the science questions
posed in this section by a significant amount. Also I don't believe
we'll do as well as what has been done for A1689. Nothing obvious
is seen in the current data. A somewhat longer integration time won't help
there.
Virial masses: also too long, as it describes other data that we want
to obtain. We could simply say that
"We are acquiring X-ray and plan to obtain SZ measurements as part of a
multiwavelength strategy of determining cluster masses through
lensing, X-ray and SZ in order to understand cluster physics and
formation."
and copy some stuff from my lensing write up about how this helps
studies of cluster abundance and cosmology.
In short I think we can condense the strong lensing section and virial
mass section in a short paragraph and tie it in with the weak lensing
as a "Determination of cluster masses" section.
Cheers,
Henk
On Thu, Jan 26, 2006 at 01:10:09PM -0800, Saul Perlmutter wrote:
> Our Cycle 14 program has now proven a new extremely efficient approach
> to obtain z>1 dust-free Type Ia supernovae, and we here propose to
> capitalize on this new technique . We will collect a total sample of
> ~20 z>1 SNe Ia in cluster ellipticals, yielding dark energy measurements
> that do not suffer from the major systematic uncertainty at these
> redshifts, that of the extinction correction with a prior. By targeting
> massive galaxy clusters at z>1, we obtain a five-times [CHECK] higher
> efficiency in detection of Type Ia supernovae in elliptical galaxies,
> and provide a well-understood host galaxy environment. These same deep
> cluster images then also yield fundamental calibrations required for
> future weak lensing and Sunyaev-Zel'dovich measurements of dark energy,
> as well as an entire program of cluster studies. The data will make
> possible a factor of two improvement on supernova constraints on dark
> energy time variation, and much larger improvement in systematic
> uncertainty, taking advantage of the uniquely well-controlled host
> environment that clusters provide. They will provide both a cluster
> dataset and a SN Ia data set that will be a longstanding scientific
> resource.
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