The mid-infrared (mid-IR) range offers an obvious and advantageous choice
in following the late-time evolution of supernovae (SNe). First, the peaks
of their spectral energy distributions (SED) shift toward the IR after the
photospheric phase; second, mid-IR observations are practically free of
interstellar extinction. Moreover, special astrophysical processes can be
traced with mid-IR observations including dust formation, as well as
interaction between the SN ejecta and the circumstellar matter (CSM).
Here I present the results of a comprehensive analysis based on far the
largest mid-IR dataset of SNe ever studied. From the sample of archive
Spitzer/IRAC images of more than 1100 SN sites, 121 SNe of various Types
have been found to appear as point sources at the images, including 48
objects with previously unpublished detection in mid-IR. The results
include statistical analysis of the mid-IR evolution of different types of
SNe, the highlighting of objects showing peculiar behavior in this
wavelength-range, as well as the modelling of SEDs, which gives insight
into whether the source of mid-IR radiation is newly-formed or
pre-existing dust, and whether the dust is heated collisionally or
radiatively.
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