The Cold Dust Content of the Oxygen-Rich Supernova Remnant G292.0+1.8
  We present far-infrared images of the Galactic oxygen-rich supernova remnant (SNR) G292.0+1.8, acquired with the PACS and SPIRE instruments of the Herschel Space Observatory. We find that the SNR shell is detected in the PACS blue (100 micron) band, but not in the red (160 micron) band, broadly consistent with results from AKARI observations. There is no discernible emission from G292.0+1.8 in SPIRE imagery at 250, 350 and 500 micron. Comparing the 100 micron emission to that observed with Spitzer, at 24 and 70 micron, we find a very similar appearance for G292.0+1.8 at all three wavelengths. The IR emission is dominated by dust from non-radiative circumstellar shocks. In addition, the radiatively shocked O-rich clump known as the 'Spur' on the eastern side of G292.0+1.8, is clearly detected in the PACS blueimages, with marginal detection in the red. Fitting the existing 14-40 micron IRS spectra of the Spur together with photometric measurements from 70 micron MIPS and 100 micron PACS photometry, we place an upper limit of <~ 0.04 solar masses, of ejecta dust mass in the Spur, under the most conservative assumption that the ejecta dust has a temperature of 15 K. Modeling the dust continuum in the IRS spectra at four positions around the rim, we estimate postshock densities ranging from n_p = 3.5 cm^-3 to 11 cm^-3. The integrated spectrum of the entire SNR, dominated by swept up circumstellar dust, can be fit with a two-component dust model with a silicate component at 62 K and graphite component at 40 K for a total dust mass of 0.023 solar masses. 
Parviz Ghavamian, Brian J. Williams
astro-ph.HE astro-ph.GA