English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Utilizing the data and tools provided through the NASA Ames PAH IRSpectroscopic Database (PAHdb), we study the PAH component of over 900Spitzer-IRS galaxy spectra. Employing a database-fitting approach, the averagePAH size, the PAH size distribution, and PAH ionization fraction are deduced.In turn, we examine their connection with the properties of the host galaxy. Wefound that PAH population within galaxies consists of middle-sized PAHs with anaverage number of carbon atoms of $\bar{N_{C}}$ = 55, and a charge statedistribution of $\sim$40% ionized - 60% neutral. We describe a correlationbetween the 6.2/11.2 $\mu$m PAH ratio with the ionization parameter($\gamma\equiv(G_{0}/n_{\rm e})(T_{\rm gas} / 1\ \mathrm{K})^{0.5}$), amoderate correlation between the 8.6/11.2 $\mu$m PAH ratio and specificstar-formation rate, and a weak anti-correlation between $\gamma$ and M$_{*}$.From the PAHdb decomposition we provide estimates for the 3.3 $\mu$m PAH band,not covered by Spitzer observations, and establish a correlation between the3.3/11.2 $\mu$m PAH ratio with N$_{\mathrm{C}}$. We further deliver a libraryof mid-IR PAH template spectra parameterized on PAH size and ionizationfraction, which can be used in galaxy spectral energy distribution fittingcodes for the modeling of the mid-IR PAH emission component in galaxies.

astrophysical journal/the astrophysical journal

Linking Characteristics of the Polycyclic Aromatic Hydrocarbon  Population with Galaxy Properties: A Quantitative Approach Using the NASA  Ames PAH IR Spectroscopic Database