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 compare the molecular and ionized gas velocity dispersion of 9 nearbyturbulent disks, analogues to high-redshift galaxies, from the DYNAMO sampleusing new ALMA and GMOS/Gemini observations. We combine our sample with 12galaxies at $z\sim $0.5-2.5 from the literature. We find that the resolvedvelocity dispersion is systematically lower by a factor $2.45\pm0.38$ for themolecular gas compared to the ionized gas, after correcting for thermalbroadening. This offset is constant within the galaxy disks and indicates theco-existence of a thin molecular and thick ionized gas disks. This result has adirect impact on the Toomre $Q$ and pressure derived in galaxies. We obtainpressures $\sim0.22$ dex lower on average when using the molecular gas velocitydispersion, $\sigma_{0,mol}$. We find that $\sigma_{0,mol}$ increases with gasfraction and star formation rate. We also obtain an increase with redshift andshow that the EAGLE and FIRE simulations overall overestimate $\sigma_{0,mol}$at high redshift. Our results suggest that efforts to compare the kinematics ofgas using ionized gas as a proxy for the total gas may overestimate thevelocity dispersion by a significant amount in galaxies at the peak of cosmicstar formation. When using the molecular gas as a tracer, our sample is notconsistent with predictions from constant efficiency star formation models,even when including transport as a source of turbulence. Feedback models withvariable star formation efficiency, $\epsilon_{ff}$, and/or feedbackefficiency, $p_*/m_*$, better predict our observations.

Systematic difference between ionized and molecular gas velocity dispersion in $z\sim1-2$ disks and local analogues