Effects of resolution and local stability on galactic disks: Halo resolution and softening on bar formation

[2603.02494] Effects of resolution and local stability on galactic disks: Halo resolution and softening on bar formation Skip to main content Search Submit Donate Log in Astrophysics > Astrophysics of Galaxies arXiv:2603.02494 (astro-ph) [Submitted on 3 Mar 2026 ( v1 ), last revised 26 Aug 2026 (this version, v3)] Title: Effects of resolution and local stability on galactic disks: Halo resolution and softening on bar formation Authors: SungWon Kwak , Ivan Minchev , Matthias Steinmetz , Sukyoung K. Yi View PDF HTML (experimental) Abstract: Using N-body simulations, we examine the impact of dark matter (DM) halo resolution and gravitational softening on bar formation. We generate isolated disk-halo systems with fixed stellar disk parameters, varying the number of halo particles, softening lengths, and halo concentration to modulate disk stability via the central DM fraction. The effects of DM resolution ($\mratio=1$, 10, and 100) on bar formation are less pronounced in more unstable disks, in which the overall evolutionary path is similar except that the lowest DM resolution model suffers gradual bar weakening. Irrespective of the halo resolution, large softening, $\epsdm$, flattens the central halo density profile within the softening scale, impeding angular momentum transfer to the nascent bar and preventing bar formation in more stable models. In unstable models with $\epsdm=0.96 \, \kpc$, a small bar still emerges due to enhanced initial instability and a larger seed perturbation, yet its strength remains capped at $F_2 \approx 0.3$ owing to unresolved central dynamical friction. Despite the destabilizing effect of reduced central DM fractions, our results indicate that deficient central angular momentum exchange can still suppress bar growth. Furthermore, halo softening influences buckling instability, as larger values ($\epsdm=0.30$ and $0.60 \, \kpc$) inhibit central vertical heating, exacerbating radial-vertical velocity dispersion anisotropies and triggering stronger buckling. We recommend adopting $ \mratio \le 10 $, $ \mstar \leq 10^4 \, \Msun $, and $ \epsdm < 0.30\,\mathrm{kpc}$ when investigating the formation and evolution of non-axisymmetric structures in Milky Way-mass galaxies. Comments: 15 pages, 12 figures. Published in A&A Subjects: Astrophysics of Galaxies (astro-ph.GA) Report number: AA59676-26 Cite as: arXiv:2603.02494 [astro-ph.GA] (or arXiv:2603.02494v3 [astro-ph.GA] for this version) https://doi.org/10.48550/arXiv.2603.02494 Focus to learn more arXiv-issued DOI via DataCite Journal reference: A&A, 712, A38 (2026) Related DOI : https://doi.org/10.1051/0004-6361/202659676 Focus to learn more DOI(s) linking to related resources Submission history From: SungWon Kwak [ view email ] [v1] Tue, 3 Mar 2026 00:55:10 UTC (6,395 KB) [v2] Mon, 22 Jun 2026 11:10:02 UTC (7,162 KB) [v3] Wed, 26 Aug 2026 21:53:08 UTC (7,162 KB) Full-text links: Access Paper: View PDF HTML (experimental) TeX Source view license Current browse context: astro-ph.GA < prev | next > new | recent | 2026-03 Change to browse by: astro-ph References & Citations SciX Google Scholar Semantic Scholar export BibTeX citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer ( What is the Explorer? ) Connected Papers Toggle Connected Papers ( What is Connected Papers? ) Litmaps Toggle Litmaps ( What is Litmaps? ) scite.ai Toggle scite Smart Citations ( What are Smart Citations? ) Code, Data, Media Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv ( What is alphaXiv? ) Links to Code Toggle CatalyzeX Code Finder for Papers ( What is CatalyzeX? ) DagsHub Toggle DagsHub ( What is DagsHub? ) GotitPub Toggle Gotit.pub ( What is GotitPub? ) Huggingface Toggle Hugging Face ( What is Huggingface? ) ScienceCast Toggle ScienceCast ( What is ScienceCast? ) Demos Demos Replicate Toggle Replicate ( What is Replicate? ) Spaces Toggle Hugging Face Spaces ( What is Spaces? ) Spaces Toggle TXYZ.AI ( What is TXYZ.AI? ) Related Papers Recommenders and Search Tools Link to Influence Flower Influence Flower ( What are Influence Flowers? ) Core recommender toggle CORE Recommender ( What is CORE? ) IArxiv recommender toggle IArxiv Recommender ( What is IArxiv? ) Author Venue Institution Topic About arXivLabs arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. 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