Solving the puzzle of subhalo spins

Wang, Yang; Lin, Weipeng; Pearce, Frazer R.; Lux, Hanni; Muldrew, Stuart I.; Onions, Julian

Abstract

Investigating the spin parameter distribution of subhalos in two high-resolution isolated halo simulations, recent work by Onions et al. suggested that typical subhalo spins are consistently lower than the spin distribution found for field halos. To further examine this puzzle, we have analyzed simulations of a cosmological volume with sufficient resolution to resolve a significant subhalo population. We confirm the result of Onions et al. and show that the typical spin of a subhalo decreases with decreasing mass and increasing proximity to the host halo center. We interpret this as the growing influence of tidal stripping in removing the outer layers, and hence the higher angular momentum particles, of the subhalos as they move within the host potential. Investigating the redshift dependence of this effect, we find that the typical subhalo spin is smaller with decreasing redshift. This indicates a temporal evolution, as expected in the tidal stripping scenario.

Citation

Wang, Y., Lin, W., Pearce, F. R., Lux, H., Muldrew, S. I., & Onions, J. (2015). Solving the puzzle of subhalo spins. Astrophysical Journal, 801(2), Article 93. https://doi.org/10.1088/0004-637X/801/2/93

• Journal Article Type: Article
• Acceptance Date: Jan 13, 2015
• Publication Date: Mar 10, 2015
• Deposit Date: May 8, 2017
• Publicly Available Date: May 8, 2017
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 801
• Issue: 2
• Article Number: 93
• DOI: https://doi.org/10.1088/0004-637X/801/2/93
• Keywords: cosmology: theory, dark matter, galaxies: evolution, galaxies: halos, methods: numerical
• Public URL: https://nottingham-repository.worktribe.com/output/747849
• Publisher URL: http://iopscience.iop.org/article/10.1088/0004-637X/801/2/93/meta
• Contract Date: May 8, 2017