Simulating the Cluster Weak Lensing Signal
Joe HollowedPhysics 526 Final PresentationUniversity of MichiganDecember 10 2019
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Cosmology from galaxy cluster masses
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Observable mass proxies:➔ X-ray temperature➔ Optical richness➔ Thermal CMB distortion
(SZ)➔ Distortion of background
sources (gravitational lensing)
High mass end of the halo population is sensitive probe of cosmology:
Cosmological Parameters from Observations of Galaxy Clusters, Allen, Evrard & Mantz, Annual Rev. of A&A, 2011
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Weak Gravitational Lensing and the Halo Profile
3Image: ESA
Strongly lensed arc
Weakly lensed
Abell S1063
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Shear magnitude is easily described under spherical symmetry of the lens:
Weak Gravitational Lensing and the Halo Profile
Projected potential, surface density, and deflection field:
Convergence Shear
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Pipeline
Generate a particle-sampled NFW
halo realization
Obtain continuous expression of the density
field
Compute lensing quantities, esp. shear
field
Fit shear profile to NFW form to recover input
parameters
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Random realizations of NFW halos
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Projected density estimation via Delaunay triangulation
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Ray-tracing through the integrated density field
Ray-tracing equation:
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Ray-tracing through the integrated density field
Deflection components: Interpolated shear field:
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Recovering the input NFW form
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Recovering the input NFW form
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Recovering the input NFW form