We analyze the cool gas in and around 14 nearby galaxies (at
The recent survey of the core-collapse supernova remnant Cassiopeia A (Cas A) with the MIRI instrument on board the James Webb Space Telescope (JWST) revealed a large structure in the interior region, referred to as the “Green Monster.” Although its location suggests that it is an ejecta structure, the infrared properties of the “Green Monster” hint at a circumstellar medium (CSM) origin. In this companion paper to the JWST Cas A paper, we investigate the filamentary X-ray structures associated with the “Green Monster” using Chandra X-ray Observatory data. We extracted spectra along the “Green Monster” as well as from shocked CSM regions. Both the extracted spectra and a principal component analysis show that the “Green Monster” emission properties are similar to those of the shocked CSM. The spectra are well fit by a model consisting of a combination of a nonequilibrium ionization model and a power-law component, modified by Galactic absorption. All the “Green Monster” spectra show a blueshift corresponding to a radial velocity of around −2300 km s−1, suggesting that the structure is on the near side of Cas A. The ionization age is around
- NSF-PAR ID:
- 10495446
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal Letters
- Volume:
- 964
- Issue:
- 1
- ISSN:
- 2041-8205
- Format(s):
- Medium: X Size: Article No. L11
- Size(s):
- ["Article No. L11"]
- Sponsoring Org:
- National Science Foundation
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