The radial alignment of dark matter subhalos: from simulations to observations

Abstract

We explore the radial alignment of subhalos in 2-dimensional projections of cosmological simulations. While most other recent studies focussed on quantifying the signal utilizing the full 3-dimensional spatial information any comparison to observational data has to be done in projection along random lines-of-sight. We have a suite of well resolved host dark matter halos at our disposal ranging from 6 x 10^14 Msun/h down to 6 x 10^13Msun/h. For these host systems we do observe that the major axis of the projected 2D mass distribution of subhalos aligns with its (projected) distance vector to the host's centre. The signal is actually stronger than the observed alignment. However, when considering only the innermost 10-20% of the subhalo's particles for the 2D shape measurement we recover the observed correlation. We further acknowledge that this signal is independent of subhalo mass.

5 pages, 4 figures, accepted for publication as MNRAS Letter

References in corpus (10)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• The spin and shape of dark matter haloes in the Millennium simulation of a LambdaCDM universe
• The Shape of the Gravitational Potential in Cold Dark Matter Halos
• The shapes, orientation, and alignment of Galactic dark matter subhalos
• Three Different Types of Galaxy Alignment within Dark Matter Halos
• Probing the Intrinsic Shape and Alignment of Dark Matter Haloes using SDSS Galaxy Groups
• Radial Alignment in Simulated Clusters
• Spatial and kinematic alignments between central and satellite halos
• The Dynamics of Subhalos in Warm Dark Matter Models
• On the relation between radial alignment of dark matter subhalos and host mass in cosmological simulations

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• The Three Hundred project: shapes and radial alignment of satellite, infalling, and backsplash galaxies
• Alignments of Group Galaxies with Neighboring Groups
• The shapes and alignments of the satellites of the Milky Way and Andromeda
• The alignment between brightest cluster galaxies and host clusters
• Mock Observations: Three Different Types of Galaxy Alignment in TNG100 Simulations