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Published January 2022 | Accepted Version + Published
Journal Article Open

SatGen – II. Assessing the impact of a disc potential on subhalo populations

Abstract

The demographics of dark matter substructure depend sensitively on the nature of dark matter. Optimally leveraging this probe requires accurate theoretical predictions regarding the abundance of subhaloes. These predictions are hampered by artificial disruption in numerical simulations, by large halo-to-halo variance, and by the fact that the results depend on the baryonic physics of galaxy formation. In particular, numerical simulations have shown that the formation of a central disc can drastically reduce the abundance of substructure compared to a dark matter-only simulation, which has been attributed to enhanced destruction of substructure due to disc shocking. We examine the impact of discs on substructure using the semi-analytical subhalo model SatGen, which accurately models the tidal evolution of substructure free of the numerical disruption that still hampers N-body simulations. Using a sample of 10 000 merger trees of Milky Way-like haloes, we study the demographics of subhaloes that are evolved under a range of composite halo–disc potentials with unprecedented statistical power. We find that the overall subhalo abundance is relatively insensitive to properties of the disc aside from its total mass. For a disc that contains 5 per cent of M_(vir), the mean subhalo abundance within r_(vir) is suppressed by ≲10 per cent relative to the no-disc case, a difference that is dwarfed by halo-to-halo variance. For the same disc mass, the abundance of subhaloes within 50 kpc is reduced by ∼30 per cent⁠. We argue that the disc mainly drives excess mass-loss for subhaloes with small pericentric radii and that the impact of disc shocking is negligible.

Additional Information

© 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2021 October 22. Received 2021 September 17; in original form 2021 May 13. Published: 28 October 2021. The authors thank Uddipan Banik and Raphaël Errani for helpful conversations throughout the development of this work. SBG is supported by the US National Science Foundation Graduate Research Fellowship under Grant No. DGE-1752134. FCvdB is supported by the National Aeronautics and Space Administration through Grant No. 17-ATP17-0028 issued as part of the Astrophysics Theory Program. FJ is supported by the Troesh Fellowship from the California Institute of Technology. Data Availability: The updated SatGen library is publicly available on GitHub.

Attached Files

Published - stab3130.pdf

Accepted Version - 2110.13044.pdf

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Additional details

Created:
August 22, 2023
Modified:
October 23, 2023