PHANGS-ML: The Universal Relation between PAH Band and Optical Line Ratios across Nearby Star-forming Galaxies
The result's identifiers
Result code in 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>
Result on the web
<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>
Alternative languages
Result language
angličtina
Original language name
PHANGS-ML: The Universal Relation between PAH Band and Optical Line Ratios across Nearby Star-forming Galaxies
Original language description
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.
Czech name
—
Czech description
—
Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10308 - Astronomy (including astrophysics,space science)
Result continuities
Project
—
Continuities
—
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Astrophysical Journal
ISSN
0004-637X
e-ISSN
1538-4357
Volume of the periodical
978
Issue of the periodical within the volume
2
Country of publishing house
GB - UNITED KINGDOM
Number of pages
32
Pages from-to
135
UT code for WoS article
001390643700001
EID of the result in the Scopus database
2-s2.0-85214669921