Orbital parameters of infalling satellite haloes in the hierarchical ΛCDM model

Jiang, L.; Cole, S.; Sawala, T.; Frenk, C.S.

Abstract

We present distributions of orbital parameters of infalling satellites of Λ cold dark matter (ΛCDM) haloes in the mass range 1012–1014 M⊙, which represent the initial conditions for the subsequent evolution of substructures within the host halo. We use merger trees constructed in a high-resolution cosmological N-body simulation to trace satellite haloes, and identify the time of infall. We find significant trends in the distribution of orbital parameters with both the host halo mass and the ratio of satellite-to-host halo masses. For all host halo masses, satellites whose infall mass is a larger fraction of the host halo mass have more eccentric, radially biased orbits. At fixed satellite-to-host halo mass ratio, high-mass haloes are biased towards accreting satellites on slightly more radial orbits. To characterize the orbital distributions fully requires fitting the correlated bivariate distribution of two chosen orbital parameters (e.g. radial and tangential velocity or energy and angular momentum). We provide simple fits to one choice of the bivariate distributions, which when transformed faithfully, captures the behaviour of any of the projected one-dimensional distributions.

Citation

Jiang, L., Cole, S., Sawala, T., & Frenk, C. (2015). Orbital parameters of infalling satellite haloes in the hierarchical ΛCDM model. Monthly Notices of the Royal Astronomical Society, 448(2), 1674-1686. https://doi.org/10.1093/mnras/stv053

• Journal Article Type: Article
• Acceptance Date: Feb 10, 2015
• Publication Date: Apr 1, 2015
• Deposit Date: Apr 15, 2015
• Publicly Available Date: Apr 16, 2015
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 448
• Issue: 2
• Pages: 1674-1686
• DOI: https://doi.org/10.1093/mnras/stv053
• Keywords: Methods: numerical, Galaxies: haloes, Cosmology: theory, Dark matter.
• Public URL: https://durham-repository.worktribe.com/output/1410038
• Related Public URLs: http://arxiv.org/abs/1409.1179