![PAH fraction anti-correlates with log([S iii]/[S ii]) (ionization parameter tracer) for thousands H ii regions in 42 PHANGS-JWST galaxies. Panel (a, b) shows all ∼ 17200 analyzed H ii regions, while ∼ 5600 brightest “resolved” H ii regions are shown on Panels (c, d). The dashed red line shows the best-fit linear regression to the “resolved” sample defined by Eq. 4. Histograms on panels (b, d) show how the logarithmic residuals after subtracting this linear trend depend on metallicity. Color on panels (a, c) denotes gas-phase oxygen abundance; red contours show the probability density of the high-metallicity (12 + log(O/H) > 8.2) points (levels correspond to 50, 65, 80, 95 and 99 percentile intervals). The Spearman correlation coefficient (ρ) and RMS scatter around the linear fit are reported on panels (a, c). -- astro-ph.GA](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/09/Polycyclic-aromatic-hydrocarbons-destruction.png?resize=1200%2C720&ssl=1)
Polycyclic aromatic hydrocarbons (PAHs) are widespread in the interstellar medium (ISM) of Solar metallicity galaxies, where they play a critical role in ISM heating, cooling, and reprocessing stellar radiation.
supernova remnant
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Status Report
A Yebes W band Line Survey Towards an Unshocked Molecular Cloud of Supernova Remnant 3C391: Evidence of Cosmic-Ray-Induced Chemistry
Cosmic rays (CRs) have strong influences on the chemistry of dense molecular clouds (MCs). To study the detailed chemistry induced by CRs, we conducted a Yebes W band line survey […]