Scylla: Observational Evidence for an Order of Magnitude in Dust-mass Opacity Evolution with Interstellar Medium Density in the Large Magellanic Cloud

Résumé fourni par la source

Abstract The emissivity of dust is known to vary greatly with radiative environment, density, grain chemistry, and geometry. Discrepancies between dust-mass surface densities derived from far-infrared (FIR) emission and visible extinction persist across and within galaxies in the local Universe. Here, we use new extinction and emission measurements toward the LMC to show that this discrepancy is driven by the dust-mass opacity evolving with the intrinsic density of the interstellar medium, and that the ratio between FIR and optical dust-mass opacity varies with gas surface density. These new findings imply that the dust-mass opacity in the FIR could increase by nearly an order of magnitude (e.g., κ 160 = 0.3–6 m 2 kg −2 ) across over an order of magnitude of total hydrogen surface density (Σ H = 4–100 M ⊙ pc −2 ), corroborating previous theoretical models for dust-mass opacity evolution in the FIR and providing new implications for emission-based dust-mass estimates.

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