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

Context: Regarding the significant interest in both dark matter and theapplication of MOND to early-type galaxies, we investigate the MOND theory bycomparing its predictions, for models of constant mass-to-light ratio, withobservational data of the early-type galaxy NGC 4649.  Aims: We study whether measurements for NGC 3379 and NGC 1399 are typical ofearly-type systems and we test the assumption of a Newtonian constant M/L ratiounderlying most of the published models.  Methods: We employ the globular clusters of NGC 4649 as a mass tracer. TheJeans equation is calculated for both MOND and constant mass-to-light ratioassumptions. Spherical symmetry is assumed and the calculations are performedfor both isotropic and anisotropic cases.  Results: We found that both Jeans models with the assumption of a constantmass-to-light ratio and different MOND models provide good agreement with theobserved values of the velocity dispersion. The most accurate fits of thevelocity dispersion were obtained for the mass-to-light ratio in the B-band,which was equal to 7, implying that there is no need for significant amounts ofdark matter in the outer parts (beyond 3 effective radii) of this galaxy. Wealso found that tangential anisotropies are most likely present in NGC 4649.

MOND vs. Newtonian dynamics in early-type galaxies. The case of NGC 4649 (M60)