Is there substructure around M87?

Abstract

We present a general method to identify infalling substructure in discrete datasets with position and line-of-sight velocity data. We exploit the fact that galaxies falling onto a brightest cluster galaxy (BCG) in a virialised cluster, or dwarf satellites falling onto a central galaxy like the Milky Way, follow nearly radial orbits. If the orbits are exactly radial, we show how to find the probability distribution for a satellite's energy, given a tracer density for the satellite population, by solving an Abel integral equation. This is an extension of Eddington (1916)'s classical formula for the isotropic distribution function. When applied to a system of galaxies, clustering in energy space can then be quantified using the Kullback-Leibler divergence, and groups of objects can be identified which, though separated in the sky, may be falling in on the same orbit. This method is tested using mock data and applied to the satellite galaxy population around M87, the BCG in Virgo, and a number of associations are found which may represent infalling galaxy groups.

9 pages, 6 figures, 2 tables. Accepted for publication in MNRAS

References in corpus (36)

• The size distribution of galaxies in the Sloan Digital Sky Survey
• Tracing Galaxy Formation with Stellar Halos I: Methods
• Minor mergers and the size evolution of elliptical galaxies
• Confirmation of the remarkable compactness of massive quiescent galaxies at z~2.3: early-type galaxies did not form in a simple monolithic collapse
• The ACS Virgo Cluster Survey. XIII. SBF Distance Catalog and the Three-Dimensional Structure of the Virgo Cluster
• Halo concentrations in the standard LCDM cosmology
• Beasts of the Southern Wild: Discovery of nine Ultra Faint satellites in the vicinity of the Magellanic Clouds
• The ACS Fornax Cluster Survey. V. Measurement and Recalibration of Surface Brightness Fluctuations and a Precise Value of the Fornax--Virgo Relative Distance
• Strong size evolution of the most massive galaxies since z~2
• A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy
• Intracluster Light in Nearby Galaxy Clusters: Relationship to the Halos of Brightest Cluster Galaxies
• The Frequency of Tidal Features Associated with Nearby Luminous Elliptical Galaxies from a Statistically Complete Sample
• Discriminating Between the Physical Processes that Drive Spheroid Size Evolution
• Dynamics of the Globular Cluster System Associated with M49 (NGC4472): Cluster Orbital Properties and the Distribution of Dark Matter
• The globular cluster system of NGC 1399 V. dynamics of the cluster system out to 80 kpc
• Quantifying Kinematic Substructure in the Milky Way's Stellar Halo
• Kinematics of SDSS subdwarfs: Structure and substructure of the Milky Way halo
• The shapes, orientation, and alignment of Galactic dark matter subhalos
• The Extended Virgo Cluster Catalog
• The virialized mass of dark matter haloes
• The ongoing assembly of a central cluster galaxy: Phase-space substructures in the halo of M87
• The Growth in Size and Mass of Cluster Galaxies since z=2
• Disassembling the Galaxy with angle-action coordinates
• The distribution function of dark matter in massive haloes
• The Orientation of Satellite Galaxies: Evidence of Elongation in the Direction of the Host
• Galaxy structure from multiple tracers: II. M87 from parsec to megaparsec scales
• The build-up of the cD halo of M87 - evidence for accretion in the last Gyr
• Action-space clustering of tidal streams to infer the Galactic potential
• Predicted Space Motions for Hypervelocity and Runaway Stars: Proper Motions and Radial Velocities for the GAIA Era
• The impact of baryonic physics on the shape and radial alignment of substructures in cosmological dark matter haloes
• Haloes light and dark: dynamical models of the stellar halo and constraints on the mass of the Galaxy
• Galactic Tides and the Shape and Orientation of Dwarf Galaxy Satellites
• Dynamical signatures of infall around galaxy clusters: a generalized Jeans equation
• Galaxy structure from multiple tracers: I. A census of M87's globular cluster populations
• On Asymmetric Distributions of Satellite Galaxies
• Reconstructing the projected gravitational potential of galaxy clusters from galaxy kinematics

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• Physical properties of SDSS satellite galaxies in projected phase-space
• Galaxy structure from multiple tracers: III. Radial variations in M87's IMF
• The Next Generation Virgo Cluster Survey (NGVS) XXXI. The kinematics of intra-cluster globular clusters in the core of the Virgo cluster
• Two-component Jaffe models with a central black hole. I: the spherical case
• The Next Generation Virgo Cluster Survey. XXXIII. Stellar Population Gradients in the Virgo Cluster Core Globular Cluster System
• Self-consistent dynamical models with a finite extent -- II. Radially truncated models
• Self-consistent dynamical models with a finite extent -- I. The uniform density sphere