some crude lensing plot

From: hoekstra@uvic.ca
Date: Tue Jan 23 2007 - 16:39:06 PST

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    Hi,

    I have been slaving away and have managed to do an extremely crude
    lensing analysis of most of the clusters (except XMM). I have
    assumed that PSF anisotropy is not present owing to the rotations
    of the fields. So no guarantees when it comes to residual systematics.

    What I did next is fit a SIS model to the tangential shear profile.
    This is tricky because ofthe small FOV and the fact that the
    cluster centre is not always obvious. The clusters are also
    typically complex in the inner regions.

    Nevertheless I was bold and also counted (again done quickly)
    "red" galaxies and plotted SIS mass vs galaxy counts.

    I have appended two plots. One with all clusters and one binned
    in n_gal. Good news: when averaging we detect the clusters, and
    in some cases we get even a decent signal for individual systems.
    Bad news: the range in counts (although crude) appears small.
    Maybe somebody who can count better can give me better numbers,
    but I think this reflects the origins of the samples. We lack
    the very massive systems.

    I haven't had time to combine the z and i data (this is all
    z band), which would increase the number of sources somewhat.
    I recall from last years discussion that reobserving these
    clusters would reduce errorbars by about 30% (as the number
    of sources increases by 60%). So that should help a bit.

    Note that the average mass is lower than the nominal 5e14
    we used last year. It's more like 2.5-3 times 10^14

    So from my perspective, there is a gain by going deeper, but
    adding some new (z=1.0-1.2) very rich clusters would help more.

    Cheers,
    Henk



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