Description
Cassiopeia A (Cas A) is the youngest core-collapse galactic supernova remnant (~350 yrs) and is amongst the closest known (~3.4 kpc). It has a secure supernova classification of Type IIb using light echo spectroscopy analysis. These make it an ideal source for studying supernova ejecta properties and its velocity distribution. We map the plasma properties of Cas A using two observations from the new XRISM satellite. The high X-ray spectral resolution capabilities of XRISM/Resolve microcalorimeter enabled a detailed characterization of H-like and He-like lines of Si and S, whose line shapes can be resolved. H-like and He-like lines are found to have systematically different Doppler shifts, likely caused by velocity differences in plasma shocked at different times. Modeling these line profiles with two-component Gaussians using Bayesian Analysis revealed distinct redshifted (backside) and blueshifted (frontside) components in the northern regions of the remnant. However, for most regions, both components were either both redshifted (northwest) or both blueshifted (southeast), consistent with the patchy ejecta shell morphology seen in optically emitting fast-moving knots. The individual line components revealed line broadening (σv) ranging from 200 to 2000 kms−1. Components with ∼1000 < σv <∼2000 kms−1 are consistent with previously determined reverse shock velocities, suggesting non-equilibrated or partially equilibrated ion temperatures. Narrow components with small radial velocities found near Cas A’s projected center likely originate from shocked CSM plasma. We also performed full plasma parameter mapping using a plane-parallel, non-equilibrium ionization (NEI) shock model and Baysian Analysis.
| Talk category | NOVA Network 3 |
|---|---|
| Preference for a talk or poster | Talk |
| Talk preference for PhD students | Second year PhD |
