Why weak lensing cluster shapes are insensitive to self-interacting dark matter

Abstract

We investigate whether the shapes of galaxy clusters inferred from weak gravitational lensing can be used as a test of the nature of dark matter. We analyse mock weak lensing data, with gravitational lenses extracted from cosmological simulations run with two different dark matter models (CDM and SIDM). We fit elliptical NFW profiles to the shear fields of the simulated clusters. Despite large differences in the distribution of 3D shapes between CDM and SIDM, we find that the distributions of weak-lensing-inferred cluster shapes are almost indistinguishable. We trace this information loss to two causes. Firstly, weak lensing measures the shape of the projected mass distribution, not the underlying 3D shape, and projection effects wash out some of the difference. Secondly, weak lensing is most sensitive to the projected shape of clusters, on a scale approaching the virial radius (~ 1.5 Mpc), whereas SIDM shapes differ most from CDM in the inner halo. We introduce a model for the mass distribution of galaxy clusters where the ellipticity of the mass distribution can vary with distance to the centre of the cluster. While this mass distribution does not enable weak lensing data to distinguish between CDM and SIDM with cluster shapes (the ellipticity at small radii is poorly constrained by weak lensing), it could be useful when modelling combined strong and weak gravitational lensing of clusters.

arXiv comment14 pages, 9 figures, submitted to MNRAS, comments welcome

References in corpus (53)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The NumPy array: a structure for efficient numerical computation
• A Universal Density Profile from Hierarchical Clustering
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The cosmological simulation code GADGET-2
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• Populating a cluster of galaxies - I. Results at z=0
• The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas
• Cosmological simulations of the growth of supermassive black holes and feedback from active galactic nuclei: method and tests
• The physics driving the cosmic star formation history
• Cluster Lensing And Supernova survey with Hubble (CLASH): An Overview
• Triaxial Modeling of Halo Density Profiles with High-resolution N-body Simulations
• Cosmological Simulations with Self-Interacting Dark Matter I: Constant Density Cores and Substructure
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• On the relation between the Schmidt and Kennicutt-Schmidt star formation laws and its implications for numerical simulations
• A Bayesian approach to strong lensing modelling of galaxy clusters
• The Frontier Fields: Survey Design
• The Shape of Dark Matter Halos: Dependence on Mass, Redshift, Radius, and Formation
• Dark Matter Halos as Particle Colliders: A Unified Solution to Small-Scale Structure Puzzles from Dwarfs to Clusters
• Cosmological Simulations with Self-Interacting Dark Matter II: Halo Shapes vs. Observations
• The BAHAMAS project: Calibrated hydrodynamical simulations for large-scale structure cosmology
• The spin and shape of dark matter haloes in the Millennium simulation of a LambdaCDM universe
• Simulating galactic outflows with kinetic supernova feedback
• Weak Gravitational Lensing with COSMOS: Galaxy Selection and Shape Measurements
• What does the Bullet Cluster tell us about self-interacting dark matter?
• A Test of the Collisional Dark Matter Hypothesis from Cluster Lensing
• The BAHAMAS project: the CMB--large-scale structure tension and the roles of massive neutrinos and galaxy formation
• Tying Dark Matter to Baryons with Self-interactions
• The overdensity and masses of the friends-of-friends halos and universality of the halo mass function
• Gravitational Lens Statistics for Generalized NFW Profiles: Parameter Degeneracy and Implications for Self-Interacting Cold Dark Matter
• Pseudo Elliptical Lensing Mass Model: Application to the NFW Mass Distribution
• Direct measurement of dark matter halo ellipticity from two-dimensional lensing shear maps of 25 massive clusters
• The Shapes and Alignments of Dark Matter Halos
• Is the Jeffreys' scale a reliable tool for Bayesian model comparison in cosmology?
• Observable tests of self-interacting dark matter in galaxy clusters: cosmological simulations with SIDM and baryons
• Make Dark Matter Charged Again
• Reconciling the Diversity and Uniformity of Galactic Rotation Curves with Self-Interacting Dark Matter
• Velocity-dependent Self-interacting Dark Matter from Groups and Clusters of Galaxies
• PyAutoLens: Open-Source Strong Gravitational Lensing
• Constraints on dark matter self-interaction from the internal density profiles of X-COP galaxy clusters
• A look to the inside of haloes: a characterisation of the halo shape as a function of overdensity in the Planck cosmology
• The ellipticity of galaxy cluster halos from satellite galaxies and weak lensing
• Fast Calculation of Gravitational Lensing Properties of Elliptical Navarro-Frenk-White and Hernquist Density Profiles
• The structure and assembly history of cluster-size haloes in Self-Interacting Dark Matter
• Constraining SIDM with halo shapes: revisited predictions from realistic simulations of early-type galaxies
• Reconciling galaxy cluster shapes, measured by theorists vs observers
• hybrid-Lenstool: A self-consistent algorithm to model galaxy clusters with strong- and weak-lensing simultaneously
• From dwarf galaxies to galaxy clusters: Self-Interacting Dark Matter over 7 orders of magnitude in halo mass
• Domain of validity for pseudo-elliptical NFW lens models
• X-Ray Shapes of Elliptical Galaxies and Implications for Self-Interacting Dark Matter
• Weak lensing ellipticities in a strong lensing regime
• Weak lensing in the blue: a counter-intuitive strategy for stratospheric observations

Cited by in corpus (5)

• Evaporation Barrier for Dark Matter in Celestial Bodies
• SIDM Concerto: Compilation and Data Release of Self-interacting Dark Matter Zoom-in Simulations
• Dark Matter Raining on DUNE and Other Large Volume Detectors
• The AIDA-TNG project: 3D halo shapes
• An Interpretable AI Framework to Disentangle Self-Interacting and Cold Dark Matter in Galaxy Clusters: The CKAN Approach