Systematic Difference between Ionized and Molecular Gas Velocity Dispersions in z similar to 1-2 Disks and Local Analogs

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F21%3A00553753" target="_blank" >RIV/67985815:_____/21:00553753 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.3847/1538-4357/abd5b9" target="_blank" >https://doi.org/10.3847/1538-4357/abd5b9</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/abd5b9" target="_blank" >10.3847/1538-4357/abd5b9</a>

Result language

angličtina

Original language name

Systematic Difference between Ionized and Molecular Gas Velocity Dispersions in z similar to 1-2 Disks and Local Analogs

Original language description

We compare the molecular and ionized gas velocity dispersions of nine nearby turbulent disks, analogs to high-redshift galaxies, from the DYNAMO sample using new Atacama Large Millimeter/submillimeter Array and GMOS/Gemini observations. We combine our sample with 12 galaxies at z similar to 0.5-2.5 from the literature. We find that the resolved velocity dispersion is systematically lower by a factor 2.45 0.38 for the molecular gas compared to the ionized gas, after correcting for thermal broadening. This offset is constant within the galaxy disks and indicates the coexistence of a thin molecular gas disk and a thick ionized one. This result has a direct impact on the Toomre Q and pressure derived in galaxies. We obtain pressures similar to 0.22 dex lower on average when using the molecular gas velocity dispersion, sigma(0,mol). We find that sigma(0,mol) increases with gas fraction and star formation rate. We also obtain an increase with redshift and show that the EAGLE and FIRE simulations overall overestimate sigma(0,mol) at high redshift. Our results suggest that efforts to compare the kinematics of gas using ionized gas as a proxy for the total gas may overestimate the velocity dispersion by a significant amount in galaxies at the peak of cosmic star formation. When using the molecular gas as a tracer, our sample is not consistent with predictions from star formation models with constant efficiency, even when including transport as a source of turbulence. Feedback models with variable star formation efficiency, epsilon(ff), and/or feedback efficiency, p(*)/m(*), better predict our observations.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

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Continuities

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Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astrophysical Journal

ISSN

0004-637X

e-ISSN

1538-4357

Volume of the periodical

909

Issue of the periodical within the volume

1

Country of publishing house

GB - UNITED KINGDOM

Number of pages

15

Pages from-to

12

UT code for WoS article

000624062600001

EID of the result in the Scopus database

2-s2.0-85103031109