A Herschel PACS and SPIRE study of the dust content of the Cassiopeia A supernova remnant

TL;DR

This study uses Herschel Space Observatory data to analyze the dust content of Cassiopeia A, revealing a cool dust component inside the remnant with a mass of 0.075 solar masses.

Contribution

First to resolve and confirm a cool (~35 K) dust component within Cassiopeia A using multi-band Herschel imaging.

Findings

Identified warm dust in the reverse shock region.

Detected cold interstellar dust knots and filaments.

Measured the mass of the cool dust component.

Abstract

Using the 3.5-m Herschel Space Observatory, imaging photometry of Cas A has been obtained in six bands between 70 um and 500 um with the PACS and SPIRE instruments, with angular resolutions ranging from 6 to 37". In the outer regions of the remnant the 70-um PACS image resembles the 24-um image Spitzer image, with the emission attributed to the same warm dust component, located in the reverse shock region. At longer wavelengths, the three SPIRE bands are increasingly dominated by emission from cold interstellar dust knots and filaments, particularly across the central, western and southern parts of the remnant. Nonthermal emission from the northern part of the remnant becomes prominent at 500 um. We have estimated and subtracted the contributions from the nonthermal, warm dust and cold interstellar dust components. We confirm and resolve for the first time a cool (~35 K) dust component, emitting at 70-160 um, that is located interior to the reverse shock region, with an estimated mass of 0.075 Msun.