PHANGS-ML: The Universal Relation between PAH Band and Optical Line Ratios across Nearby Star-forming Galaxies

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A90106%2F25%3A00646366" target="_blank" >RIV/67985815:90106/25:00646366 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.3847/1538-4357/ad972a" target="_blank" >https://doi.org/10.3847/1538-4357/ad972a</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/ad972a" target="_blank" >10.3847/1538-4357/ad972a</a>

Jazyk výsledku

angličtina

Název v původním jazyce

PHANGS-ML: The Universal Relation between PAH Band and Optical Line Ratios across Nearby Star-forming Galaxies

Popis výsledku v původním jazyce

The structure and chemistry of the dusty interstellar medium (ISM) are shaped by complex processes that depend on the local radiation field, gas composition, and dust grain properties. Of particular importance are polycyclic aromatic hydrocarbons (PAHs), which emit strong vibrational bands in the mid-infrared, and play a key role in the ISM energy balance. We recently identified global correlations between PAH band and optical line ratios across three nearby galaxies, suggesting a connection between PAH heating and gas ionization throughout the ISM. In this work, we perform a census of the PAH heating-gas ionization connection using similar to 700,000 independent pixels that probe scales of 40-150 pc in 19 nearby star-forming galaxies from the PHANGS survey. We find a universal relation between log PAH(11.3 mu m/7.7 mu m) and log ([S ii]/H alpha) with a slope of similar to 0.2 and a scatter of similar to 0.025 dex. The only exception is a group of anomalous pixels that show unusually high (11.3 mu m/7.7 mu m) PAH ratios in regions with old stellar populations and high starlight-to-dust emission ratios. Their mid-infrared spectra resemble those of elliptical galaxies. Active galactic nucleus hosts show modestly steeper slopes, with a similar to 10% increase in PAH(11.3 mu m/7.7 mu m) in the diffuse gas on kiloparsec scales. This universal relation implies an emerging simplicity in the complex ISM, with a sequence that is driven by a single varying property: the spectral shape of the interstellar radiation field. This suggests that other properties, such as gas-phase abundances, gas ionization parameter, and grain charge distribution, are relatively uniform in all but specific cases.

Název v anglickém jazyce

PHANGS-ML: The Universal Relation between PAH Band and Optical Line Ratios across Nearby Star-forming Galaxies

Popis výsledku anglicky

The structure and chemistry of the dusty interstellar medium (ISM) are shaped by complex processes that depend on the local radiation field, gas composition, and dust grain properties. Of particular importance are polycyclic aromatic hydrocarbons (PAHs), which emit strong vibrational bands in the mid-infrared, and play a key role in the ISM energy balance. We recently identified global correlations between PAH band and optical line ratios across three nearby galaxies, suggesting a connection between PAH heating and gas ionization throughout the ISM. In this work, we perform a census of the PAH heating-gas ionization connection using similar to 700,000 independent pixels that probe scales of 40-150 pc in 19 nearby star-forming galaxies from the PHANGS survey. We find a universal relation between log PAH(11.3 mu m/7.7 mu m) and log ([S ii]/H alpha) with a slope of similar to 0.2 and a scatter of similar to 0.025 dex. The only exception is a group of anomalous pixels that show unusually high (11.3 mu m/7.7 mu m) PAH ratios in regions with old stellar populations and high starlight-to-dust emission ratios. Their mid-infrared spectra resemble those of elliptical galaxies. Active galactic nucleus hosts show modestly steeper slopes, with a similar to 10% increase in PAH(11.3 mu m/7.7 mu m) in the diffuse gas on kiloparsec scales. This universal relation implies an emerging simplicity in the complex ISM, with a sequence that is driven by a single varying property: the spectral shape of the interstellar radiation field. This suggests that other properties, such as gas-phase abundances, gas ionization parameter, and grain charge distribution, are relatively uniform in all but specific cases.

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

2025

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

978

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

32

Strana od-do

135

Kód UT WoS článku

001390643700001

EID výsledku v databázi Scopus

2-s2.0-85214669921