A Catalogue of Galactic Supernova Remnants in the far-infrared:
  revealing ejecta dust in pulsar wind nebulae
  We search for far-infrared (FIR) counterparts of known supernova remnants
(SNRs) in the Galactic plane (10 deg <| l |< 60 deg) at 70-500 micron using the
Herschel Infrared Galactic Plane Survey (Hi-GAL). Of 71 sources studied, we
find that 29 (41 per cent) SNRs have a clear FIR detection of dust emission
associated with the SNR. Dust from 8 of these is in the central region, and 4
indicate pulsar wind nebulae (PWNe) heated ejecta dust. A further 23 have dust
emission in the outer shell structures which is potentially related to swept up
material. Many Galactic SNe have dust signatures but we are biased towards
detecting ejecta dust in young remnants and those with a heating source (shock
or PWN). We estimate the dust temperature and mass contained within three PWNe,
G11.2-0.3, G21.5-0.9, and G29.7-0.3 using modified blackbody fits. To more
rigorously analyse the dust properties at various temperatures and dust
emissivity index beta, we use point process mapping (PPMAP). We find
significant quantities of cool dust (at 20-40 K) with dust masses of Md = 0.34
+/- 0.14 solar mass, Md = 0.29 +/- 0.08 solar mass, and Md = 0.51 +/- 0.13
solar mass for G11.2-0.3, G21.5-0.9, and G29.7-0.3 respectively. We derive the
dust emissivity index for the PWN ejecta dust in G21.5-0.3 to be beta = 1.4 +/-
0.5 compared to dust in the surrounding medium where beta = 1.8 +/- 0.1.
