Spatial variations of dust abundances across the Large Magellanic Cloud
  Using the data obtained with the Spitzer Space telescope as part of the
Surveying the Agents of a Galaxy's Evolution (SAGE) legacy survey, we have
studied the variations of the dust composition and abundance across the Large
Magellanic Cloud (LMC). Such variations are expected, as the explosive events
which have lead to the formation of the many HI shells observed should have
affected the dust properties. Using a model and comparing with a reference
spectral energy distribution from our Galaxy, we deduce the relative abundance
variations of small dust grains across the LMC. We examined the infrared color
ratios as well as the relative abundances of very small grains (VSGs) and
polycyclic aromatic hydrocarbons (PAHs) relative to the big grain (BG)
abundance. Results show that each dust component could have different origins
or evolution in the interstellar medium (ISM). The VSG abundance traces the
star formation activity and could result from shattering of larger grains,
whereas the PAH abundance increases around molecular clouds as well as in the
stellar bar, where they could have been injected into the ISM during mass loss
from old stars.
