2021/02/19 by Nicholas Pavanel, Jeremy J. Webb · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Local Group #Milky Way #Orbit (dynamics) #Physics #Stellar, planetary, and galactic studies #Velocity dispersion #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stab461
published in Monthly Notices of the Royal Astronomical Society 503(2), 1932-1939 (Oxford University Press) · 9 pages, 7 figures, 1 table, accepted for publication in MNRAS
openalex publication_date 2021/02/19 · arxiv created 2021/02/22 · openalex created_date 2021/03/01 · arxiv updated 2021/03/03 · openalex updated_date 2026/08/05
ABSTRACT We present a comprehensive study on how perturbations due to a distribution of Lambda cold dark matter (ΛCDM) dark matter subhalos can lead to star clusters deviating from their orbits. Through a large suite of massless test particle simulations, we find that (i) subhalos with masses less than 108 M⊙ negligibly affect test particle orbits, (ii) perturbations lead to orbital deviations only in environments with substructure fractions f sub ≥ 1 \rm per cent, (iii) perturbations from denser subhalos produce larger orbital deviations, and (iv) subhalo perturbations that are strong relative to the background tidal field lead to larger orbital deviations. To predict how the variation in test particle orbital energy σe(t) increases with time, we test the applicability of theory derived from single-mass subhalo populations to populations where subhalos have a mass spectrum. We find σe(t) can be predicted for test particle evolution within a mass spectrum of subhalos by assuming subhalos all have masses equal to the mean subhalo mass and by using the local mean subhalo separation to estimate the change in test particle velocities due to subhalo interactions. Furthermore, the orbital distance variation at an orbital distance r can be calculated via σ r=2.98 × 10-5 ± 8 × 10-8 (\rm kpc-1 km-2 s2) × r × σ e with a dispersion about the line of best-fitting equalling 0.08 kpc. Finally, we conclude that clusters that orbit within 100 kpc of Milky Way-like galaxies experience a change no greater than 2 \rm per cent in their dissolution times.