A dust twin of Cas A: cool dust and 21 μm silicate dust feature in the supernova remnant G54.1+0.3

We present infrared (IR) and submillimetre observations of the Crab-like supernova remnant (SNR) G54.1+0.3 including 350 mu m (SHARC-II), 870 mu m (LABOCA), 70, 100, 160, 250, 350, and 500 mu m (Herschel), and 3-40 mu m (Spitzer). We detect dust features at 9, 11, and 21 mu m and a long-wavelength continuum dust component. The 21 mu m dust coincides with [Ar II] ejecta emission, and the feature is remarkably similar to that in Cas A. The IRAC 8 mu m image including Ar ejecta is distributed in a shell-like morphology which is coincident with dust features, suggesting that dust has formed in the ejecta. We create a cold dust map that shows excess emission in the northwestern shell. We fit the spectral energy distribution of the SNR using the continuous distributions of ellipsoidal grain model of pre-solar grain SiO2 that reproduces the 21 and 9 mu m dust features and discuss grains of silicon carbide and polycyclic aromatic hydrocarbon that may be responsible for the 10-13 mu m dust features. To reproduce the long-wavelength continuum, we explore models consisting of different grains including Mg2SiO4, MgSiO3, Al2O3, FeS, carbon, and Fe3O4. We tested a model with a temperature-dependent silicate absorption coefficient. We detect cold dust (27-44 K) in the remnant, making this the fourth such SNR with freshly formed dust. The total dust mass in the SNR ranges from 0.08 to 0.9 M-circle dot depending on the grain composition, which is comparable to predicted masses from theoretical models. Our estimated dust masses are consistent with the idea that SNe are a significant source of dust in the early Universe.