Ecology of dark matter haloes -II. Effects of interactions on the alignment of halo pairs

Abstract

We use the Horizon Run 4 cosmological N -body simulation to study the effects of distant and close interactions on the alignments of the shapes, spins, and orbits of targets haloes with their neighbours, and their dependence on the local density environment and neighbour separation. Interacting targets have a significantly lower spin and higher sphericity and oblateness than all targets. Interacting pairs initially have anti-parallel spins, but the spins develop parallel alignment as time goes on. Neighbours tend to evolve in the plane of rotation of the target, and in the direction of the major axis of prolate haloes. Moreover, interactions are preferentially radial, while pairs with non-radial orbits are preferentially prograde. The alignment signals are stronger at high-mass and for close separations, and independent on the large-scale density. Positive alignment signals are found at redshifts up to 4, and increase with decreasing redshifts. Moreover, the orbits tend to become prograde at low redshift, while no alignment is found at high redshift (z = 4).

Accepted for Publication in MNRAS

References in corpus (12)

• The spin and shape of dark matter haloes in the Millennium simulation of a LambdaCDM universe
• The Evolution of Dark Matter Halo Properties in Clusters, Filaments, Sheets and Voids
• Spin alignment of dark matter haloes in filaments and walls
• The spin and orientation of dark matter halos within cosmic filaments
• The Large-Scale Orientations of Disk Galaxies
• The Alignments of the Galaxy Spins with the Real-Space Tidal Field Reconstructed from the Two Mass Redshift Survey
• Spin alignments of spiral galaxies within the large-scale structure from SDSS DR7
• Cosmic web alignments with the shape, angular momentum and peculiar velocities of dark matter haloes
• Probing the Intrinsic Shape and Alignment of Dark Matter Haloes using SDSS Galaxy Groups
• Transformation of Morphology and Luminosity Classes of the SDSS Galaxies
• Alignments between galaxies, satellite systems and haloes
• Alignments of Group Galaxies with Neighboring Groups

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• Living with Neighbors. III. The Origin of the Spin$-$Orbit Alignment of Galaxy Pairs: A Neighbor versus the Large-scale Structure
• Living with Neighbors. IV. Dissecting the Spin$-$Orbit Alignment of Dark Matter Halos: Interacting Neighbors and the Local Large-scale Structure
• Living with Neighbors. V. Better-aligned Spiral+Spiral Galaxy Pairs Show Stronger Star Formation
• Spin Alignment of Dark Matter Halos: Mad Halos