Intrinsic shapes of Brightest Cluster Galaxies

Abstract

We discuss the statistical distribution of galaxy shapes and viewing angles under the assumption of triaxiality by deprojecting observed Surface Brightness (SB) profiles of 56 Brightest Cluster Galaxies coming from a recently published large deep-photometry sample. For the first time, we address this issue by directly measuring axis ratio profiles without limiting ourselves to a statistical analysis of average ellipticities. We show that these objects are strongly triaxial, with triaxiality parameters 0.39 $\le T\le$ 0.72, have on average axis ratios $<p(r)>=$ 0.84 and $<q(r)>=$ 0.68, and are more spherical in the central regions but flatten out at large radii. Measured shapes in the outskirts agree well with the shapes found for simulated massive galaxies and their dark matter halos from both the IllustrisTNG and the Magneticum simulations, possibly probing the nature of dark matter. In contrast, both simulations fail to reproduce the observed inner regions of BCGs, producing too flattened objects.

arXiv commentv2, 27 pages, 9 Figures. Published in ApJ, vol. 933, p. 215

References in corpus (32)

• First results from the IllustrisTNG simulations: matter and galaxy clustering
• First results from the IllustrisTNG simulations: the stellar mass content of groups and clusters of galaxies
• First results from the IllustrisTNG simulations: the galaxy color bimodality
• First results from the IllustrisTNG simulations: A tale of two elements -- chemical evolution of magnesium and europium
• First results from the IllustrisTNG simulations: radio haloes and magnetic fields
• The optical morphologies of galaxies in the IllustrisTNG simulation: a comparison to Pan-STARRS observations
• Cosmological simulations of black hole growth: AGN luminosities and downsizing
• Statistical Properties of Collisionless Equal- and Unequal-Mass Merger Remnants of Disk Galaxies
• The Size Evolution of Star-forming and Quenched Galaxies in the IllustrisTNG simulation
• Connecting Angular Momentum and Galactic Dynamics: The complex Interplay between Spin, Mass, and Morphology
• Observable tests of self-interacting dark matter in galaxy clusters: cosmological simulations with SIDM and baryons
• The Atlas3D project - XXIV. The intrinsic shape distribution of early-type galaxies
• The Co-Evolution of Total Density Profiles and Central Dark Matter Fractions in Simulated Early-Type Galaxies
• On determining the shape of matter distributions
• Kinematics of Simulated Galaxies I: Connecting Dynamical and Morphological Properties of Early-Type Galaxies at Different Redshifts
• Structural Evolution of Early-type Galaxies to z=2.5 in CANDELS
• The SAMI Galaxy Survey: comparing 3D spectroscopic observations with galaxies from cosmological hydrodynamical simulations
• Evidence from Intrinsic Shapes for Two Families of Elliptical Galaxies
• Structure of Brightest Cluster Galaxies and Intracluster Light
• The Dependence of Galaxy Shape on Luminosity and Surface Brightness Profile
• The different growth pathways of Brightest Cluster Galaxies and the Intra-Cluster Light
• The stellar halos of ETGs in the IllustrisTNG simulations: the photometric and kinematic diversity of galaxies at large radii
• The origin and properties of massive prolate galaxies in the Illustris simulation
• The MASSIVE Survey - X. Misalignment between Kinematic and Photometric Axes and Intrinsic Shapes of Massive Early-Type Galaxies
• The Morphology-Density-Relation: Impact on the Satellite Fraction
• The MASSIVE Survey IX: Photometric Analysis of 35 High Mass Early-Type Galaxies with HST WFC3/IR
• A novel approach to optimize the regularization and evaluation of dynamical models using a model selection framework
• SDSS-IV MaNGA: The intrinsic shape of slow rotator early-type galaxies
• SMART: A new implementation of Schwarzschild's Orbit Superposition technique for triaxial galaxies and its application to an N-body merger simulation
• Non-parametric Triaxial Deprojection of Elliptical Galaxies
• On the Uncertainties of the Central Density in Axisymmetric Galaxies due to Deprojection
• A simple data-driven method to optimise the penalty strengths of penalised models and its application to non-parametric smoothing

Cited by in corpus (2)

• Accuracy and precision of triaxial orbit models I: SMBH mass, stellar mass and dark-matter halo
• Sensitivity of Halo Shape Measurements