Re: Possible z > 1 target cluster

From: Henk Hoekstra (hoekstra@uvic.ca)
Date: Wed Oct 26 2005 - 14:58:14 PDT

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    Hi Kyle, et al.

    Yes, Mike is right. Basically two clusters along the line of sight
    means we won't get any accurate masses... There is such a thing as
    having too much!

    Although it might be great for the SNe (although the magnifications of
    SNe in the high-z cluster might be too uncertain to use them for
    cosmology anyway), it is bad for the cluster work. Depending how
    close they are in projection, this would also complicate Xray and SZ
    followup.

    Consequently I would prefer going after a more suitable target.

    Cheers,
    Henk

    On Wed, Oct 26, 2005 at 02:53:03PM -0700, Mike Gladders wrote:
    > With a cluster in the forground along the line of sight the lensing boost
    > in the "weak" regime (relevant for most of the ACS field of view) can be
    > on order of 10-100% depending on how close you are to the foreground
    > cluster. The few percent you quote is probably more relevant for a
    > standard random line of sight - having a known cluster in place changes
    > things rather significantly...
    >
    > Mike
    >
    > On Wed, 26 Oct 2005, Kyle S Dawson wrote:
    >
    > > Is the z=1.2 cluster close enough to the foreground cluster cl1604+4321 to fit them both in the FOV of ACS?
    > > How many foreground galaxies associated with the supercluster would fall into the 3' FOV if the ACS were
    > > centered on the z=1.2 cluster? I believe the effects due to lensing are not that significant, on the order of a few
    > > percent, and those negative effects would be outweighted by the high density of galaxies in the projection
    > > along the line of sight of two clusters.
    > > -Kyle
    > >
    > >
    > > ----- Original Message -----
    > > From: Lori Lubin <lubin@physics.ucdavis.edu>
    > > Date: Wednesday, October 26, 2005 5:23 pm
    > > Subject: Possible z > 1 target cluster
    > >
    > > >
    > > > As part of our DEIMOS survey of the CL1604 supercluster at z = 0.9 (of
    > > > which one of our SN targets CL1604+4304 at z = 0.90 is a member), we
    > > > discovered a background cluster at z = 1.17. We have 37 confirmed
    > > > members,with a velocity dispersion of ~850 km/s. This cluster is
    > > > located near
    > > > another SC member, CL1604+4321 at z = 0.92. It may be an interesting
    > > > target because of the existing number of redshifts and the
    > > > possibility of
    > > > getting SN at z = 0.9 at the same time, although the lensing due to
    > > > theintervening structure may make this target too complicated.
    > > >
    > > > Regards,
    > > >
    > > > Lori
    > > >
    > > >
    > > >
    > >



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