English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

(Abridged) Dynamical friction can be used to distinguish Newtonian gravityand modified Newtonian dynamics (MOND) because it works differently in theseframeworks. This concept, however, has yet to be explored very much with MOND.Previous simulations showed weaker dynamical friction during major mergers forMOND than for Newtonian gravity with dark matter. Analytic arguments suggestthe opposite for minor mergers. In this work, we verify the analyticpredictions for MOND by high-resolution $N$-body simulations of globularclusters (GCs) moving in isolated ultra-diffuse galaxies (UDGs). We test theMOND analog of the Chandrasekhar formula for the dynamical friction proposed byS\'anchez-Salcedo on a single GC. We also explore whether MOND allows GCsystems of isolated UDGs to survive without sinking into nuclear star clusters.The simulations are run using the adaptive-mesh-refinement code Phantom ofRamses. The mass resolution is $20\,M_\odot$ and the spatial resolution$50\,$pc. The GCs are modeled as point masses. Simulations including a singleGC reveal that, as long as the apocenter of the GC is over about 0.5 effectiveradii, the S\'anchez-Salcedo formula works excellently, with an effectiveCoulomb logarithm increasing with orbital circularity. Once the GC reaches thecentral kiloparsec, its sinking virtually stops, likely because of the corestalling mechanism. In simulations with multiple GCs, many of them sink towardthe center, but the core stalling effect seems to prevent them from forming anuclear star cluster. The GC system ends up with a lower velocity dispersionthan the stars of the galaxy. By scaling the simulations, we extend theseresults to most UDG parameters, as long as these UDGs are not external-fielddominated.

Evolution of globular-cluster systems of ultra-diffuse galaxies due to dynamical friction in MOND gravity