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

MOdified Newtonian dynamics (MOND) represents a phenomenological alternativeto dark matter (DM) for the missing mass problem in galaxies and clusters ofgalaxies. We analyze the central regions of a local sample of $\sim 220$early-type galaxies from the $\rm ATLAS^{3D}$ survey, to see if the data can bereproduced without recourse to DM. We estimate dynamical masses in the MONDcontext through Jeans analysis, and compare to $\rm ATLAS^{3D}$ stellar massesfrom stellar population synthesis. We find that the observed stellarmass--velocity dispersion relation is steeper than expected assuming MOND witha fixed stellar initial mass function (IMF) and a standard value for theacceleration parameter $a_{\rm 0}$. Turning from the space of observables tomodel space, a) fixing the IMF, a universal value for $a_{\rm 0}$ cannot befitted, while, b) fixing $a_{\rm 0}$ and leaving the IMF free to vary, we findthat it is "lighter" (Chabrier-like) for low-dispersion galaxies, and "heavier"(Salpeter-like) for high dispersions. This MOND-based trend matches inferencesfrom Newtonian dynamics with DM, and from detailed analysis of spectralabsorption lines, adding to the converging lines of evidence for asystematically-varying IMF.

MOND and IMF variations in early-type galaxies from $ATLAS^{3D}$