Advisors: Tom Broadhurst, Yoel Rephaeli Using “Weak Lensing Dilution” to Improve Measurements of Luminous and Dark Matter in A1689 Medezinski et al. 2007 Elinor Medezinski Advisors: Tom Broadhurst, Yoel Rephaeli Collaborators: Keiichi Umetsu, Narciso Benitez, Dan Coe, Holland Ford, Nobuo Arimoto, Xu Kong Technion, July 25th 2007
Motivation Clusters mass - important cosmological tool Mass distribution within clusters – cluster formation history Probes of baryonic and dark matter Cluster merger events – physical processes
Methods Measure mass and light of z<0.5 clusters with weak-lensing Carefull cluster separation Dilution effect Combine strong, weak lensing analysis
Gravitational Lensing The lens equation Image Source Observer Lens
A1689 Subaru SuprimeCam 34’x27’ HST ACS 3.3’x3.3’ Chandra ACIS 30’ Weak-lensing A1689 z = 0.183 Subaru SuprimeCam 34’x27’ HST ACS 3.3’x3.3’ Chandra ACIS Strong-lensing 30’ Arcs
Lensing Mapping - Shear - Convergence
a,b semi-major/minor axes Weak Lensing Shear Reduced shear – image ellipticity a,b semi-major/minor axes
Weak Lensing Shear Tangential shear – measured relative to cluster center
Color-magnitude Red Cluster sequence E/SO sequence galaxies Blue
Previous work Weak-lensing profile for A1689, CFH12K, Bardeau et al. 2005 Use only magnitude-cut 21.6<R<24.7
Color-magnitude E/SO sequence galaxies Three galaxy samples Red - background Blue - faint background Green – cluster +background Red Blue
Setting limits Distortion reduces closer to the cluster sequence
Distortion of bright cluster galaxies, i<21.5 mag – zero signal gT=0.0043
Weak Lensing Distortion Background - Distortion declines gradually with radius Green – distortion diluted by unlensed cluster members The “Dilution” effect
Weak Lensing Distortion ACS (r<2’) +Subaru Saw-tooth pattern of strong lensing Max – tangential critical curve, ~47’’ Min – radial critical curve, ~17’’
Fraction = Cluster Membership Dilution to measure cluster membership Correct for red/blue relative depths
Cluster Luminosity Profile Cluster luminosity – “g-weighted” flux to get cluster flux Flux Luminosity Linear fit
Cluster Color Cluster color – “g-weighted” color Bluer at large radii
M*/L vs. color from Bell et al. 2003 Mass to Light Ratio High M/L ~ 480 Agrees with M/L inside 2’ from Broadhurst et al. 2005a Mass estimates from lensing M/M* Mass profile from Broadhurst et al. 2005a,b M*/L vs. color from Bell et al. 2003
Cluster Luminosity Function Flat, no upturn
Distortion profile fits NFW profile Best fit: High concentration
Redshift magnification Redshift decreases with cluster radius Lensing magnification effect Breaks the mass-sheet degeneracy <z>
Lensing-Depth Relation Background red galaxies are systematically less distorted than background blue - Depth effect
The Capak catalog Multicolor images from Subaru of HDF-N photometric redshifts Capak et al., 2004
Redshift distribution Depth ratio
Weak Lensing scaling Can constrain cosmology from distortion ratio Depend on cosmology: Can constrain cosmology from distortion ratio =
Summary Have determined light profile, color profile and radial luminosity functions of A1689 reliably, with no need to resolve the cluster sequence based on color. Constructed flat luminosity function, with no need for far-field counts for background subtraction Deduced high NFW concentration Future work: Obtain photo-z’s using more colors for consistency checks. Extend to other clusters (CL0024,A370,A1703…) using existing Subaru and ACS data. Constrain mass distribution by combining X-ray data and SZ effect.
Next Cluster – A1703