Star formation efficiency in nearby galaxies revealed with a new CO-to-H2 conversion factor prescription

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A90106%2F24%3A00617526" target="_blank" >RIV/67985815:90106/24:00617526 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.3847/1538-4357/ad10ae" target="_blank" >https://doi.org/10.3847/1538-4357/ad10ae</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/ad10ae" target="_blank" >10.3847/1538-4357/ad10ae</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Star formation efficiency in nearby galaxies revealed with a new CO-to-H2 conversion factor prescription

Popis výsledku v původním jazyce

Determining how the galactic environment, especially the high gas densities and complex dynamics in bar-fed galaxy centers, alters the star formation efficiency (SFE) of molecular gas is critical to understanding galaxy evolution. However, these same physical or dynamical effects also alter the emissivity properties of CO, leading to variations in the CO-to-H-2 conversion factor (alpha(CO)) that impact the assessment of the gas column densities and thus of the SFE. To address such issues, we investigate the dependence of alpha(CO) on the local CO velocity dispersion at 150 pc scales using a new set of dust-based alpha(CO) measurements and propose a new alpha(CO) prescription that accounts for CO emissivity variations across galaxies. Based on this prescription, we estimate the SFE in a sample of 65 galaxies from the PHANGS-Atacama Large Millimeter/submillimeter Array survey. We find increasing SFE toward high-surface-density regions like galaxy centers, while using a constant or metallicity-based alpha(CO) results in a more homogeneous SFE throughout the centers and disks. Our prescription further reveals a mean molecular gas depletion time of 700 Myr in the centers of barred galaxies, which is overall three to four times shorter than in nonbarred galaxy centers or the disks. Across the galaxy disks, the depletion time is consistently around 2-3 Gyr, regardless of the choice of alpha(CO) prescription. All together, our results suggest that the high level of star formation activity in barred centers is not simply due to an increased amount of molecular gas, but also to an enhanced SFE compared to nonbarred centers or disk regions.

Název v anglickém jazyce

Star formation efficiency in nearby galaxies revealed with a new CO-to-H2 conversion factor prescription

Popis výsledku anglicky

Determining how the galactic environment, especially the high gas densities and complex dynamics in bar-fed galaxy centers, alters the star formation efficiency (SFE) of molecular gas is critical to understanding galaxy evolution. However, these same physical or dynamical effects also alter the emissivity properties of CO, leading to variations in the CO-to-H-2 conversion factor (alpha(CO)) that impact the assessment of the gas column densities and thus of the SFE. To address such issues, we investigate the dependence of alpha(CO) on the local CO velocity dispersion at 150 pc scales using a new set of dust-based alpha(CO) measurements and propose a new alpha(CO) prescription that accounts for CO emissivity variations across galaxies. Based on this prescription, we estimate the SFE in a sample of 65 galaxies from the PHANGS-Atacama Large Millimeter/submillimeter Array survey. We find increasing SFE toward high-surface-density regions like galaxy centers, while using a constant or metallicity-based alpha(CO) results in a more homogeneous SFE throughout the centers and disks. Our prescription further reveals a mean molecular gas depletion time of 700 Myr in the centers of barred galaxies, which is overall three to four times shorter than in nonbarred galaxy centers or the disks. Across the galaxy disks, the depletion time is consistently around 2-3 Gyr, regardless of the choice of alpha(CO) prescription. All together, our results suggest that the high level of star formation activity in barred centers is not simply due to an increased amount of molecular gas, but also to an enhanced SFE compared to nonbarred centers or disk regions.

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

2024

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

961

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

11

Strana od-do

42

Kód UT WoS článku

001142454100001

EID výsledku v databázi Scopus

2-s2.0-85184189358