Astrochemistry

The Resolved Behavior of Dust Mass, Polycyclic Aromatic Hydrocarbon Fraction, and Radiation Field in ~ 800 Nearby Galaxies

By Keith Cowing

Status Report

astro-ph.GA

October 8, 2024

Filed under astro-ph.GA, astrochemistry, astronomy, dust, Herschel, Interstellar, PAH, Polycyclic Aromatic Hydrocarbons, Spectroscopy, WISE

The Resolved Behavior of Dust Mass, Polycyclic Aromatic Hydrocarbon Fraction, and Radiation Field in ~ 800 Nearby Galaxies — Two-dimensional fits of U, qPAH, and Σd as a function of a combination of the resolved stellar mass and star formation rate. Top row: 2D histograms of the Σ⋆–ΣSFR plane, where the bin values show the average U (left column), qPAH (center column), and Σd (right column). The light bins are calculated for all pixels passing the 3σ S/N cut, and the bright bins are calculated for pixels passing that same cut and that that have Σ⋆ and ΣSFR above the completeness thresholds. The 2D fit uses the standard deviations within each bin as errors in the linear regression. Bottom row: The x-axis shows the best-fit using both Σ⋆ and ΣSFR. The y-axis shows the observed data. The best-fit coefficients are reported in Table 5. — astro-ph.GA

We present resolved 3.6−250 μm dust spectral energy distribution (SED) fitting for ∼800 nearby galaxies. We measure the distribution of radiation field intensities heating the dust, the dust mass surface density (Σ_d), and the fraction of dust in the form of polycyclic aromatic hydrocarbons (PAHs; q_PAH).

We find that the average interstellar radiation field (U) is correlated both with stellar mass surface density (Σ⋆) and star formation rate surface density (Σ_SFR), while more intense radiation fields are only correlated with Σ_SFR.

We show that q_PAH is a steeply decreasing function of Σ_SFR, likely reflecting PAH destruction in H II regions. Galaxy integrated q_PAH is strongly, negatively correlated with specific star formation rate (s_SFR) and offset from the star-forming “main sequence” (ΔMS), suggesting that both metallicity and star formation intensity play a role in setting the global q_PAH.

We also find a nearly constant Md/M⋆ ratio for galaxies on the main sequence, with a lower ratio for more quiescent galaxies, likely due to their lower gas fractions. From these results, we construct prescriptions to estimate the radiation field distribution in both integrated and resolved galaxies.

We test these prescriptions by comparing our predicted U to results of SED fitting for stacked “main sequence” galaxies at 0<z<4 from Béthermin et al. (2015) and find s_SFR is an accurate predictor of U even at these high redshifts.

Finally, we describe the public delivery of matched-resolution WISE and Herschel maps along with the resolved dust SED fitting results through the InfraRed Science Archive (IRSA).

Jérémy Chastenet, Karin M. Sandstrom, Adam K. Leroy, Caroline Bot, I-Da Chiang, Ryan Chown, Karl D. Gordon, Eric W. Koch, Hélène Roussel, Jessica Sutter, Thomas G. Williams

Comments: Accepted in ApJS; 38 pages, 15 figures + 2 Appendices. The data will be hosted at IPAC under DOI this https URL. The link to the delivery this https URL will be online soon!
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2410.03835 [astro-ph.GA] (or arXiv:2410.03835v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2410.03835
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Submission history
From: Jérémy Chastenet
[v1] Fri, 4 Oct 2024 18:03:21 UTC (3,405 KB)
https://arxiv.org/abs/2410.03835
Astrobiology, Astrochemistry,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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