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

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

—

Rok uplatnění

2021

Kód důvěrnosti údajů

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

Název periodika

Astrophysical Journal

ISSN

0004-637X

e-ISSN

1538-4357

Svazek periodika

909

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

15

Strana od-do

12

Kód UT WoS článku

000624062600001

EID výsledku v databázi Scopus

2-s2.0-85103031109