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

We investigate the anisotropy of the stellar velocity dispersions within theeffective radius, $R_{\rm e}$, in 24 ATLAS$^{\rm 3D}$ pure-bulge galaxies, 16of which are kinematic slow rotators (SRs). We allow the spherical anisotropyparameter $\beta$ to be radially varying and allow a radial gradient in thestellar mass-to-light ratio ($M_\star/L$) through the parameter $K$ introducedearlier. The median anisotropy for SRs depends on $K$ as follows:$\langle\beta_{\rm m}\rangle = a + b K$ with $a=0.19\pm 0.05$, $b=-0.13\pm0.07$ ($\Lambda$CDM) or $a=0.21\pm 0.05$, $b=-0.26\pm 0.08$ (MOND), where$\beta_{\rm m}$ refers to the radially averaged quantity. Under the$\Lambda$CDM paradigm this scaling is tied to a scaling of $\langle f_{\rmDM}\rangle = (0.16\pm 0.03) +(0.31\pm 0.06) K$, where $f_{\rm DM}$ refers tothe DM fraction within a sphere of $r=R_{\rm e}$. For $K=0$ (constant$M_\star/L$), we obtain radially biased results with $\langle\beta_{\rmm}\rangle \approx 0.2$ consistent with previous results. However, marginalizingover $0 < K < 1.5$ yields $\langle\beta_{\rm m}\rangle = 0.06 ^{+0.11}_{-0.14}$with $\langle f_{\rm DM}\rangle = 0.35 \pm 0.08$: isotropy is preferred. Thisisotropy hides the fact that $\beta_{\rm m}$ is correlated with kinematicfeatures such as counter rotating cores (CRCs), kinematically distinct cores(KDCs), and low-level velocities (LVs): SRs with LVs are likely to be radiallybiased while SRs with CRCs are likely to be tangentially biased, and SRs withKDCs are intermediate. Existing cosmological simulations allow us to understandthese results qualitatively in terms of their dynamical structures andformation histories although there exist quantitative tensions. More realisticcosmological simulations, particularly allowing for $M_\star/L$ gradients, maybe required to better understand SRs.

astrophysical journal/the astrophysical journal

Modeling Nearly Spherical Pure-Bulge Galaxies with a Stellar  Mass-to-Light Ratio Gradient under the $\Lambda$CDM and MOND Paradigms: II.  The Orbital Anisotropy of Slow Rotators within the Effective Radius