Kpc-scale properties of dust temperature in terms of dust mass and star formation activity

We investigate how dust temperature is affected by local environmental quantities, especially dust surface density (sigma(dust)), dust-to-gas ratio (D/G), and interstellar radiation field. We compile multiwavelength observations in 46 nearby galaxies, uniformly processed with a common physical resolution of 2 kpc. A physical dust model is used to fit the infrared dust emission spectral energy distribution (SED) observed with WISE and Herschel. The star formation rate (SFR) is traced with GALEX ultraviolet data corrected by WISE infrared. We find that the dust temperature correlates well with the SFR surface density (sigma(SFR)), which traces the radiation from young stars. The dust temperature decreases with increasing D/G at fixed sigma(SFR), as expected from stronger dust shielding at high D/G, when sigma(SFR) is higher than similar to 2 x 10(-3 )M(?) yr(-1)kpc(-2). These measurements are in good agreement with the dust temperature predicted by our proposed analytical model. Below this range of sigma(SFR), the observed dust temperature is higher than the model prediction and is only weakly dependent on D/G, possibly due to dust heating from an old stellar population or the variation of SFR within the past 10(10) yr. Overall, the dust temperature as a function of sigma(SFR) and sigma(dust) predicted by our analytical model is consistent with observations. We also notice that, at fixed gas surface density, sigma(SFR) tends to increase with D/G, i.e. we can modify the Kennicutt-Schmidt law empirically with a dependence on D/G to match observations better.

Automated summary

We investigated the impact of local environmental factors, particularly dust surface density (sigma(dust)), dust-to-gas ratio (D/G), and interstellar radiation field, on the dust temperature. By analyzing multiwavelength observations in 46 nearby galaxies, we found that the dust temperature is strongly correlated with the surface density of star formation rate (sigma(SFR)), which is indicative of radiation from young stars. Additionally, the dust temperature decreases as D/G increases, suggesting stronger dust shielding at higher D/G values. Our findings are consistent with the predictions of our proposed analytical model.