Dust Formation Observed in Young Supernova Remnants with Spitzer

Abstract

We present dust features and masses observed in young supernova remnants (SNRs) with Spitzer Infrared Spectrograph (IRS) mapping and staring observations of four youngest supernova remnants: SNR 1E102.2-7219 (E0102) in the Small Magellanic Cloud (SMC), Cas A and G11.2-0.3 in our Galaxy, and N132D in the Large Magellanic Cloud (LMC). The spectral mapping data revealed a number of dust features which include 21 micron-peak dust and featureless dust in Cas A and 18-micron peak dust in E0102 and N132D. The 18 micron-peak feature is fitted by a mix of MgSiO_3 and solid Si dust grains, while the 21-micron peak dust is by a mix of silicates and FeO; we also explore dust fitting using Continuous Distribution of Ellipsoid grain models. We report detection of CO fundamental band from Cas A in near-infrared. We review dust features observed and identified in other SNRs. The dust emission is spatially correlated with the ejecta emission, showing dust is formed in SN ejecta. The spectra of E0102 show rich gas lines from ejecta including strong ejecta lines of Ne and O, including two [Ne III] lines and two [Ne V] lines which allow us to diagnostic density and temperature of the ejecta and measure the ejecta masses. E0102 and N132D show weak or lacking Ar, Si, and Fe ejecta, whereas the young Galactic SNR Cas A show strong Ar, Si, and S and weak Fe. We discuss compositions and masses of dust and association with those of ejecta and finally, dust contribution from SNe to early Universe.

Files

Additional details