Towards an accurate cluster cosmology with photometric galaxy surveys<\/p>\n\n\n\n
speaker: Tomomi Sunayama<\/p>\n\n\n\n
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Abstract: <\/p>\n\n\n\n
Galaxy\u00a0clusters\u00a0are the most massive gravitationally self-bound objects in the Universe. These\u00a0clusters\u00a0form at the rare high peaks of the primordial density fluctuations, and they subsequently trace the growth of structure in the Universe as they grow in mass and abundance. As such,\u00a0clusters\u00a0constitute a natural\u00a0cosmological\u00a0probe for constraining the properties of the primordial fluctuations as well as\u00a0cosmological\u00a0parameters including the nature of dark energy.\u00a0Clusters\u00a0are, however, also known to be susceptible to many systematics such as selection biases and projection effects.We develop a new analysis pipeline which is full forward modeling of\u00a0cluster\u00a0observables (abundance,\u00a0clustering, and lensing signals) with an empirical model for the projection effects (i.e., interloper galaxies along the line-of-sight are misidentified as genuine members of the\u00a0cluster). The projection effects alter the mass-observable relation as well as boost the amplitude of\u00a0clustering\u00a0and lensing signals due to the anisotropic distribution of optical\u00a0clusters. We validate our model on simulations and then apply it to the SDSS redMaPPer cluster\u00a0catalog whose result favors low Omega-m and high sigma8. We discuss possible implications using Subaru HSC lensing measurements.<\/p>\n","protected":false},"excerpt":{"rendered":"