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Full strength of (weak) Cluster lensing. Elinor Medezinski Tel Aviv University. Advisors: Tom Broadhurst, Yoel Rephaeli Collaborators: Keiichi Umetsu, Narciso Benitez, Dan Coe, Holland Ford, Masamune Oguri, Andy Taylor Granada CLASH team meeting, Sep 21 st , 2010.
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Full strength of (weak) Cluster lensing Elinor Medezinski Tel Aviv University Advisors: Tom Broadhurst, Yoel Rephaeli Collaborators: Keiichi Umetsu, Narciso Benitez, Dan Coe, Holland Ford, Masamune Oguri, Andy Taylor Granada CLASH team meeting, Sep 21st, 2010 Medezinski et al. 2007, Medezinski et al. 2010a, Medezinski et al. 2010b (submitted)
Subaru data reduction For each filter of each cluster • use Subaru pipeline: • Renaming • Overscan and bias subtraction • Making flat frames • Flat fielding • Distortion and atmospheric dispersion correction • PSF size measurement • PSF size equalization • Sky subtraction • Masking out AG probe • Masking out bad regions • Alignment • Co-adding • Derive zeropoints • Catalog making: SExtractor (ColorPro) + imcat shapes (KSB) influence WL shape measurements and magnitudes influence WL shape measurements influence WL shape measurements influence WL shape measurements and magnitudes and magnitudes influence WL shape measurements and magnitudes
Subaru Cluster Dataset Status 8.5 clusters done
Weak Lensing Dilution • Oguri et al. 2009 • Diluted by a factor of ~2 in the center • Leads to underestimated Einstein radius • Leads to underestimated Cvir A1703
Weak lensing profiles • gT profiles – • rising background signal • ~zero for green – diluted by unlensed cluster members A370 Red – background Blue – background Green– cluster +~background Pink – foreground +background Weak lensing measured using IMCAT (Umetsu & Broadhurst 2008, Umetsu, Medezinski et al. 2010) “Dilution” method • Cluster membership – almost ~100% for entire radius range, →green sample is comprised mostly of cluster.
Setting limits • Distortion reduces closer to the cluster sequence Blue sample upper limit Red sample lower limit
Luminosity & M/L profiles • A1689 • A1703 • A370 • RXJ1347-11 • 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)
Weak lensing samples • Select background galaxy samples – “orange”, “green” ”red”, “blue”, and “dropouts” and measure their lensing profile Grey–foreground Orange– background Green– background Red – background Blue – background Pink – background (high-z dropouts) A370
Fit background WL distortion profile with power law: Find amplitude ai for other samples, with same power law Bright Grey–foreground Orange– background Green– background Red – background Blue – background Pink – background (high-z dropouts) Faint
Grey–foreground Orange– background Green– background Red – background Blue – background Pink – background (high-z dropouts) COSMOS Redshifts 30-band wide field (2 sq. deg.) survey (Capak et al. 2007) Photometric redshifts catalog (Ilbert et al. 2009) mean redshift in color-color space Same selection samples
Samples photo-z distributions • Separated redshift bins • Selection in different field Grey–foreground Orange– background Green– background Red – background Blue – background Pink – background (high-z dropouts)
COSMOS vs. GOODS • General agreement • Low-z peak mostly erroneous • Examine low-z contamination vs. color limit to make cuts
WL and redshift vs. magnitude • Red increases as expected • Blue decreases – sign of shape underestimation at faint mags • Dds/Ds agrees – cannot determine redshifts accurately beyond z’~25 Grey–foreground Orange– background Green– background Red – background Blue – background Pink – background (high-z dropouts)
Faint Bright Results: • gT amplitude vs. redshift overlaid on the lensing distance – redshift curves • Using 25 A370’s - Δw≈0.6 A370 ZwCl0024-17 RXJ1347-11
Summary • 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 determine the lensing distance – redshift relation, and thereby constraining cosmological parameters – Δw≈0.6. Recent & Future work: • Obtain photo-z’s using more colors for consistency checks. • Determine methods uncertainties due to shapes, redshifts, sample selection etc w/ simulations. • Combine w/ strong-lensing from MCT/CLASH. • Constrain mass distribution by combining X-ray (Lemze et al. 2008) and SZ (Umetsu et al. 2009).