From: Henk Hoekstra (hoekstra@uvic.ca)
Date: Thu Jan 25 2007 - 20:19:10 PST
Hi Marc,
I am glad you like the mass-richness plot. We have been looking
at the scatter as well. Some scatter seems to be coming from the
three RDCS clusters (blue points) but the high point is cluster
G from IRAC. However, we also colorcoded based on redshift and
when I did that, the high-z (z>1.2) clusters all end up at the
low n_gal range, with a large scatter.
In the case of such high redshifts, foreground projections can
become a nuisance. We have no solid evidence, but I would wonder
whether that is the case for cluster G. So we don't understand
why it is off the relation, but on the other hand, one would
expect such outlyers to happen. Either from projections, or
selection effects that may bias us to look at systems that are
along filaments. I hope this helps with you queasiness...
I am not sure I can provide a good sentence to describe this, but
if somebody has a good suggestion, please let us know.
By the way, n_gal is the number of early type galaxies in the ACS
field (Kyle can correct me, as he measured it). I guess we need
to define this in the figure caption.
Cheers,
Henk
> Fig 3b (weak-lens mass vs optical richness) is impressive. The only
> queasiness I have is staring at the high mass (8+ x10^14) point at
> ngal=20. Do we understand why that cluster is so off the relation?
> The mass error bar suggests the mass uncertainty is not enough to
> explain it. The scatter in the Mass-ngal relation seems to jump below
> ngal =20. If this is due to the mass estimates becoming less reliable
> shouldn't that be reflected in larger errors? I don't suggest we need
> to discuss this at any length but if someone could enlighten me that
> would be good - and if it can also be done by adding a well crafted
> sentence to the caption that would be helpful.
>
> Cheers,
> Marc
>
> On Jan 25, 2007, at 5:28 PM, Nino Panagia wrote:
>
> >I must admit that it makes me proud to be part of the team because it
> >looks VERY good, and reads VERY well.
> >
>
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