2025/11/14 by Pan, Ruiyu, Arkaprabha Sarangi, Sarangi, Arkaprabha
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #High Energy Astrophysical Phenomena (astro-ph.HE)
paper · pdf · doi:10.48550/arxiv.2511.11835
openalex publication_date 2025/11/14 · openalex created_date 2025/11/19 · openalex updated_date 2026/07/28
We forward-model rest-frame 8--20 μm JWST/MIRI MRS spectra of 25 active galactic nuclei (AGN) with a three-dimensional radiative-transfer library in order to compare radial dust-density laws of the form n(r)∝ r-p over p=0.5--2.0. Within our tempered grid-based comparison, the model scores do not identify a single radial profile that is preferred for all sources. Instead, 20 of the 25 sources have their largest normalized tempered weights at p≤1, while five have their highest scores at p≥1.5, suggesting that both more extended and more centrally concentrated effective MIR-emitting dust distributions may be represented in the sample. The silicate feature shows a second systematic trend: absorption minima remain close to the canonical 9.7 μm wavelength, whereas emission peaks are shifted redward by about 1 μm, consistent with a combination of radiative-transfer effects and dust processing in the illuminated inner regions. By contrast, the effective obscuring-geometry parameters are more tightly clustered within the adopted grid: the fitted opening-angle values cluster at 30^∘--40^∘, and 24 sources have the intermediate radial-extent grid value Y = 100. These results suggest that variations in the radial dust distribution and effective dust properties are important contributors to the observed MIR spectral diversity, while the fitted opening-angle parameter is comparatively clustered within the adopted model framework.