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CCAPP Seminar: Benedikt Diemer (University of Maryland)

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January 24, 2023
12:00PM - 1:00PM
PRB 4138

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Add to Calendar 2023-01-24 12:00:00 2023-01-24 13:00:00 CCAPP Seminar: Benedikt Diemer (University of Maryland) Title: A dynamics-based density profile for dark matter halos Abstract: The dark matter density profiles of cluster halos carry signatures of their mass, dynamical state, andeven of the nature of dark matter. Some of the most interesting signals reside at large radii (aroundthe virial radius and beyond), which have recently become observationally accessible via satellitedistributions and weak lensing. However, to harness the rapid progress promised by futureinstruments such as VRO/LSST and Roman, we need to significantly upgrade our theoreticalunderstanding of the expected signals. One key roadblock has been the superposition of orbiting andinfalling dark matter particles in simulations, which obscures the true shape of the orbiting (1-halo)term near the cluster edge. Based on a novel algorithm to split simulated halos into their dynamicalcomponents, I will introduce an accurate, more physical fitting function for profiles out to large radii.I will show how the best-fit parameters are related to the halo properties of interest, providing apractical framework for deriving cluster properties such as the mass accretion rate from profileobservations. PRB 4138 Center for Cosmology and AstroParticle Physics (CCAPP) ccapp@osu.edu America/New_York public

Title: A dynamics-based density profile for dark matter halos

Abstract:

The dark matter density profiles of cluster halos carry signatures of their mass, dynamical state, andeven of the nature of dark matter. Some of the most interesting signals reside at large radii (aroundthe virial radius and beyond), which have recently become observationally accessible via satellitedistributions and weak lensing. However, to harness the rapid progress promised by futureinstruments such as VRO/LSST and Roman, we need to significantly upgrade our theoreticalunderstanding of the expected signals. One key roadblock has been the superposition of orbiting andinfalling dark matter particles in simulations, which obscures the true shape of the orbiting (1-halo)term near the cluster edge. Based on a novel algorithm to split simulated halos into their dynamicalcomponents, I will introduce an accurate, more physical fitting function for profiles out to large radii.I will show how the best-fit parameters are related to the halo properties of interest, providing apractical framework for deriving cluster properties such as the mass accretion rate from profileobservations.

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