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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Using the final MaNGA sample (DR17) of 10K galaxies, we investigate the darkmatter fraction $f_{\rm DM}$ within one half-light radius $R_{\rm e}$ for about6K galaxies with good kinematics spanning a wide range of morphologies andstellar velocity dispersion ($1.6\lesssim \lg\,\sigma_{\rme}/\mathrm{km\,s^{-1}}\lesssim 2.6$). We employ two techniques to estimate$f_{\rm DM}$: (i) Jeans Anisotropic Modelling (JAM), which performs dark matterdecomposition based on the stellar kinematics and (ii) comparing the totaldynamical mass-to-light ratios $(M/L)_{\rm JAM}$ and the $(M_{\ast}/L)_{\rmSPS}$ from Stellar Population Synthesis (SPS). We find that both methodsconsistently show a significant trend of increasing $f_{\rm DM}$ withdecreasing $\sigma_{\rm e}$, for $\lg(\sigma_{\rme}/\mathrm{km\,s^{-1}})\lesssim2.1$ and very low $f_{\rm DM}$ at larger$\sigma_{\rm e}$. For the 235 early-type galaxies with the best dynamicalmodels, we explore the variation of the stellar initial mass function (IMF) bycomparing the stellar mass-to-light ratios $(M_{\ast}/L)_{\rm JAM}$ from JAMand SPS. We confirm that the stellar mass excess $\alpha_{\rm IMF}\equiv(M_{\ast}/L)_{\rm JAM}/(M_{\ast}/L)_{\rm SPS}$, which reflects the IMF shape,increases with $\sigma_{\rm e}$, in agreement with previous studies thatreported a transition from Chabrier-like to Salpeter IMF among galaxies. Wealso detect weak positive correlations between $\alpha_{\rm IMF}$ and age, butno correlations with metallicity ($[Z/H]$). Finally, we stack galaxy spectraaccording to their $\alpha_{\rm IMF}$ to search for differences inIMF-sensitive spectral features (e.g. the $\rm Na_{\rm I}$ doublet). We onlyfind marginal evidence for such differences, which casts doubt on the validityof one or both methods to measure the IMF.

MaNGA DynPop -- V. The dark-matter fraction versus stellar velocity  dispersion relation and initial mass function variations: dynamical models  and full spectrum fitting of integral-field spectroscopy