Associations of dwarf galaxies in a $\Lambda$CDM Universe

Abstract

Associations of dwarf galaxies are loose systems composed exclusively of dwarf galaxies. These systems were identified in the Local Volume for the first time more than thirty years ago. We study these systems in the cosmological framework of the $\Lambda$ Cold Dark Matter ($\Lambda$CDM) model. We consider the Small MultiDark Planck simulation and populate its dark matter haloes by applying the semi-analytic model of galaxy formation SAG. We identify galaxy systems using a friends of friends algorithm with a linking length equal to $b=0.4\mathrm{Mpc}{h}^{-1}$, to reproduce the size of dwarf galaxy associations detected in the Local Volume. Our samples of dwarf systems are built up removing those systems that have one (or more) galaxies with stellar mass larger than a maximum threshold $M_{\max }$. We analyse three different samples defined by ${\log }_{10}(M_{\max }[{\mathrm{M}}_{\odot }{h}^{-1}])=8.5,9.0$ and $9.5$. On average, our systems have typical sizes of $\sim 0.2\mathrm{Mpc}{h}^{-1}$, velocity dispersion of $\sim 30\mathrm{km}{\mathrm{s}}^{-1}$ and estimated total mass of $\sim 10^{11}{\mathrm{M}}_{\odot }{h}^{-1}$. Such large typical sizes suggest that individual members of a given dwarf association reside in different dark matter haloes and are generally not substructures of any other halo. Indeed, in more than 90 per cent of our dwarf systems their individual members inhabit different dark matter haloes, while only in the remaining 10 per cent members do reside in the same halo. Our results indicate that the $\Lambda$CDM model can naturally reproduce the existence and properties of dwarf galaxies associations without much difficulty.

arXiv comment9 pages, 7 figures. Accepted for publication in MNRAS

References in corpus (36)

• Planck 2013 results. XVI. Cosmological parameters
• The Seventh Data Release of the Sloan Digital Sky Survey
• LSST: from Science Drivers to Reference Design and Anticipated Data Products
• Populating a cluster of galaxies - I. Results at z=0
• The 2dF Galaxy Redshift Survey: Spectra and redshifts
• The Rockstar Phase-Space Temporal Halo Finder and the Velocity Offsets of Cluster Cores
• Galactic star formation and accretion histories from matching galaxies to dark matter haloes
• The DESI Experiment Part I: Science,Targeting, and Survey Design
• MultiDark simulations: the story of dark matter halo concentrations and density profiles
• The Arecibo Legacy Fast ALFA Survey: I. Science Goals, Survey Design and Strategy
• Gravitationally Consistent Halo Catalogs and Merger Trees for Precision Cosmology
• The 6dF Galaxy Survey: Samples, Observational Techniques and the First Data Release
• Updated Nearby Galaxy Catalog
• The properties of warm dark matter haloes
• The distribution of stellar mass in the low-redshift Universe
• Chemical enrichment of the intra-cluster and intergalactic medium in a hierarchical galaxy formation model
• Simulations of the galaxy population constrained by observations from z=3 to the present day: implications for galactic winds and the fate of their ejecta
• Galaxy Groups within 3500 km s${}^{-1}$
• On the galaxy stellar mass function, the mass-metallicity relation, and the implied baryonic mass function
• Associations of Dwarf Galaxies
• Effects of AGN feedback on LCDM galaxies
• Semi-Analytic Galaxies - I. Synthesis of environmental and star-forming regulation mechanisms
• Galaxy Groups
• Metal Enrichment of the ICM: a 3-D Picture of Chemical and Dynamical Properties
• Chemo-Archaeological Downsizing in a Hierarchical Universe: Impact of a Top Heavy IGIMF
• Satellites and Haloes of Dwarf Galaxies
• Ram pressure stripping in a galaxy formation model. I. A novel numerical approach
• The Frequency of Dwarf Galaxy Multiples at Low Redshift in SDSS vs. Cosmological Expectations
• Calibration of semi-analytic models of galaxy formation using Particle Swarm Optimization
• An Improved Model for the Dynamical Evolution of Dark Matter Subhaloes
• Binary Galaxies in the Local Supercluster and Its Neighborhood
• Light to Mass Variations with Environment
• The Impact of Gas Stripping and Stellar Mass Loss on Satellite Galaxy Evolution
• Cosmic CARNage I: on the calibration of galaxy formation models
• Galaxy Pairs in the Local Group
• Semi-analytic galaxies -- III. The impact of supernova feedback on the mass-metallicity relation

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