The Dust Mass of Supernova Remnants in M31
  The dust temperature and mass of the supernova remnants (SNRs) in M31 are
estimated by fitting the infrared spectral energy distribution calculated from
the images in the Spitzer/IRAC4 and MIPS24, Herschel/PACS70, 100, 160, and
Herschel/SPIRE250, 350$\mu$m band. Twenty SNRs with relatively reliable
photometry exhibit an average dust temperature of $20.1^{+1.8}_{-1.5}$K, which
is higher than the surrounding and indicating the heating effect of supernova
explosion. The dust mass of these SNRs ranges from about 100 to 800$
M_{\odot}$, much bigger than the SNRs in the Milky Way. On the other hand, this
yields the dust surface density of $0.10^{+0.07}_{-0.04}{ M_{\odot} \rm
pc^{-2}}$, about half of the surrounding area, which implies that about half
dust in the SNRs is destroyed by the supernova explosion. The dust temperature,
the radius, and thus the dust mass all demonstrate that the studied SNRs are
old and very likely in the snowplow or even fade away phase because of the
limitation by the far distance and observation resolution of M31, and the
results can serve as a reference to the final effect of supernova explosion on
the surrounding dust.
