Full strength of (weak) Cluster lensing

Full strength of (weak) Full strength of (weak) Cluster lensingCluster lensing

Advisors: Tom Broadhurst, Yoel RephaeliCollaborators: Keiichi Umetsu, Narciso Benitez, Dan Coe,

Holland Ford, Masamune Oguri

Medezinski et al. 2007, Broadhurst et al. 2008,Medezinski et al. 2009, Medezinski et al. 2010 (in prep)

Elinor MedezinskiElinor MedezinskiTel Aviv UniversityTel Aviv University

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New approach - Color-ColorNew approach - Color-Color

• B,R,z’ for A370• V,R,z’ for RXJ1347• g’,r’,i’ for A1703

(Medezinski et al. 2009)

• Galaxy number density map

• 4 Density peaks – different galaxy populations

A370

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Average radius in Color-Color Average radius in Color-Color spacespace

• Color code = distance from cluster center

• Blue = low mean radius – cluster galaxies

A370

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Sample selection in Color-ColorSample selection in Color-Color

• Red – background• Blue – background• Green – cluster

+~background• Pink – foreground

+background

A370

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Weak lensing profilesWeak lensing profilesA370• gT profiles –

•rising background signal

•~zero for green – diluted by unlensed cluster members

• Cluster membership – almost ~100% for entire radius range,

→green sample is comprised mostly of cluster.

G

B

Green

clcl D

D

Backg

Greeng

N

Nf

1““Dilution” Dilution” methodmethod

• Red – background• Blue – background• Green – cluster

+~background• Pink – foreground

+background

Weak lensing measured using IMCAT (Umetsu & Broadhurst 2008, Umetsu, Medezinski et al. 2010)

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Dilution in other workDilution in other work

• Oguri et al. 2009

• Diluted by a factor of ~2 in the center

• Leads to underestimated Einstein radius

• Leads to underestimated Cvir

A1703

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• gT-profiles agree

• NFW fits give high concentrations (Cvir=rvir/rs)

than expected by ΛCDM N-body simulations

• Use magnification to check consistency of gT results

Broadhurst et al. 2008

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NFW parametersNFW parameters• Cvir-Mvir

comparison with

other studies

and ΛCDM

• 4σ discrepancy with ΛCDM, even considering orientation and selection bias (Hennawi et al 2007, Oguri & Blanford et al. 2009)

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Luminosity & M/L profilesLuminosity & M/L profiles

• Cluster luminosity – “g-weighted” flux to get cluster flux

• Flux Luminosity• Linear fit• M/L goes down in the

outskirts – morphology-density related effect (Dressler 1980)

rg

gFFrF

Bi

Gi

Gi

i

Gicl

)(

•A1689

*A1703

A370

♦RXJ1347-11

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Weak lensing strength vs. redshiftWeak lensing strength vs. redshifttest of cosmology using WL distortionstest of cosmology using WL distortions

(Medezinski et al. 2010 in prep)(Medezinski et al. 2010 in prep)

In the weak limit,

Lensing distance vs. redshift:

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Weak lensing samplesWeak lensing samples• Select background galaxy samples –”red”,

“blue”, “green” and “dropouts” and measure their lensing profile

A370• Red – background• Blue – background• Green – background• Pink – background

(high-z dropouts)

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COSMOS RedshiftsCOSMOS Redshifts

• 30-band wide field (2 sq. deg.) survey (Capak et al. 2007)

• Photometric redshifts catalog (Ilbert et al. 2009)

• Same selection samples• mean redshift in color-

color space

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• gT amplitude vs. redshift overlaid on the lensing distance – redshift curves

RXJ1347-11

A370

ZwCl0024-17

Faint

Bright

Results:Results:

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SummarySummary• Developed new scheme to resolve cluster/foreground/background selected in color-color space and better

determine weak lensing profiles.

• Determined light profiles & radial luminosity functions of A1689, A1703, A370, RXJ1347 reliably, with no need to resolve the cluster sequence based on color.

• Found flat luminosity function, with no need for far-field counts for background subtraction.

• Constructed M/L profiles to the virial radius, showing physical behavior of DM to light distributions, dropping to the center of cluster, and also dropping to the outskirts.

• Deduced high NFW concentrations, contradicting ΛCDM simulation expectation values.

• Use weak lensing distortions to constrain the lensing distance – redshift relation.

Future work:

• Obtain photo-z’s using more colors for consistency checks.

• Extend to other clusters (CL0024 submitted Umetsu et al. 2009, MACS sample) using existing Subaru.

• Combine w/ strong-lensing from HST/ACS (Zitrin et al. 2009) – Hubble MCT proposal accepted!! – 25 clusters with 525 orbits.

• Constrain mass distribution by combining X-ray and SZ from Chandra and Amiba (Amiba paper - Umetsu et al. 2009).