Orateur
Description
Observing galaxies in millimeter continuum emission is vital to study the physical properties of the dusty interstellar medium as it provides constraints on the low-frequency end of the dust spectral energy distribution (SED). We present observations of NGC2146 (starburst spiral) and NGC2976 (peculiar dwarf) with the NIKA2 camera on the IRAM-30m telescope, as part of the IMEGIN guaranteed time large program. Combined with available FIR and radio continuum observations, we model the radio-to-infrared SEDs of these two galaxies, both globally and locally, using a Bayesian method. The total dust mass estimated is $4.88\times10^7 M_{\odot}$ and $1.02\times 10^6 M_{\odot}$ in NGC2146 and NGC2976, respectively. We find a Galactic value for the dust emissivity index in the center of NGC2146 decreasing towards its outer disk. It is however flatter and smoothly distributed in NGC2976. We present calibration relations between mm emission and star formation rate (SFR). We also present a dust-to-gas ratio (DGR) map for NGC2976 and find a reverse relation between DGR and dust temperature. Lastly, we deduce an important role of the radiation field and star formation feedback in the shattering and dissociation of dust grains and the molecular-to-atomic gas ratio in the dwarf galaxy.
