Revisiting the dust properties in the molecular clouds of the Large Magellanic Cloud. (arXiv:1905.09622v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Paradis_D/0/1/0/all/0/1">D. Paradis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Meny_C/0/1/0/all/0/1">C. Mény</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Juvela_M/0/1/0/all/0/1">M. Juvela</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Noriega_Crespo_A/0/1/0/all/0/1">A. Noriega-Crespo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ristorcelli_I/0/1/0/all/0/1">I. Ristorcelli</a>
In this present analysis we investigate the dust properties associated with
the different gas phases (including the ionized phase this time) of the LMC
molecular clouds at 1$^{prime}$ angular resolution (four times greater than a
previous analysis) and with a larger spectral coverage range thanks to Herschel
data. We also ensure the robustness of our results in the framework of various
dust models. We performed a decomposition of the dust emission in the infrared
(3.6 $mic$ to 500 $mic$) associated with the atomic, molecular, and ionized
gas phases in the molecular clouds of the LMC. The resulting spectral energy
distributions were fitted with four distinct dust models. We then analyzed the
model parameters such as the intensity of the radiation field and the relative
dust abundances, as well as the slope of the emission spectra at long
wavelengths. This work allows dust models to be compared with infrared data in
various environments for the first time, which reveals important differences
between the models at short wavelengths in terms of data fitting (mainly in the
PAH bands). In addition, this analysis points out distinct results according to
the gas phases, such as dust composition directly affecting the dust
temperature and the dust emissivity in the submm, and different dust emission
in the near-infrared (NIR). We observe direct evidence of dust property
evolution from the diffuse to the dense medium in a large sample of molecular
clouds in the LMC. In addition, the differences in the dust component
abundances between the gas phases could indicate different origins of grain
formation. We also point out the presence of a NIR-continuum in all gas phases,
with an enhancement in the ionized gas. We favor the hypothesis of an
additional dust component as the carrier of this continuum.
In this present analysis we investigate the dust properties associated with
the different gas phases (including the ionized phase this time) of the LMC
molecular clouds at 1$^{prime}$ angular resolution (four times greater than a
previous analysis) and with a larger spectral coverage range thanks to Herschel
data. We also ensure the robustness of our results in the framework of various
dust models. We performed a decomposition of the dust emission in the infrared
(3.6 $mic$ to 500 $mic$) associated with the atomic, molecular, and ionized
gas phases in the molecular clouds of the LMC. The resulting spectral energy
distributions were fitted with four distinct dust models. We then analyzed the
model parameters such as the intensity of the radiation field and the relative
dust abundances, as well as the slope of the emission spectra at long
wavelengths. This work allows dust models to be compared with infrared data in
various environments for the first time, which reveals important differences
between the models at short wavelengths in terms of data fitting (mainly in the
PAH bands). In addition, this analysis points out distinct results according to
the gas phases, such as dust composition directly affecting the dust
temperature and the dust emissivity in the submm, and different dust emission
in the near-infrared (NIR). We observe direct evidence of dust property
evolution from the diffuse to the dense medium in a large sample of molecular
clouds in the LMC. In addition, the differences in the dust component
abundances between the gas phases could indicate different origins of grain
formation. We also point out the presence of a NIR-continuum in all gas phases,
with an enhancement in the ionized gas. We favor the hypothesis of an
additional dust component as the carrier of this continuum.
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