2013/03/22 by Satoru Katsuda, Yutaka Ohira, Koji Mori +5 · 19 citations
Chemistry · Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Cassiopeia A #Chemistry #Ejecta #Ion #Ionization #Physics #Protein filament #Spectral line #Supernova #Supernova remnant #astro-ph.HE
paper · pdf · doi:10.1088/0004-637x/768/2/182
published in The Astrophysical Journal 768(2), 182 (IOP Publishing) · 21 pages, 7 figures, accepted for publication in The Astrophysical Journal
arxiv created 2013/03/22 · openalex publication_date 2013/04/26 · arxiv updated 2015/06/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
Using the unprecedented spectral resolution of the reflection grating spectrometer (RGS) on board XMM-Newton , we reveal dynamics of X-ray-emitting ejecta in the oxygen-rich supernova remnant Puppis A. The RGS spectrum shows prominent K-shell lines, including O vii Heα forbidden and resonance, O viii Lyα, O viii Lyβ, and Ne ix Heα resonance, from an ejecta knot positionally coincident with an optical oxygen-rich filament (the so-called Ω filament) in the northeast of the remnant. We find that the line centroids are blueshifted by 1480 ± 140 ± 60 km s −1 (the first and second term errors are measurement and calibration uncertainties, respectively), which is fully consistent with that of the optical Ω filament. Line broadening at 654 eV (corresponding to O viii Lyα) is obtained to be σ ≲ 0.9 eV, indicating an oxygen temperature of ≲ 30 keV. Analysis of XMM-Newton MOS spectra shows an electron temperature of ∼0.8 keV and an ionization timescale of ∼2 × 10 10 cm −3 s. We show that the oxygen and electron temperatures as well as the ionization timescale can be reconciled if the ejecta knot was heated by a collisionless shock whose velocity is ∼600–1200 km s −1 and was subsequently equilibrated due to Coulomb interactions. The RGS spectrum also shows relatively weak K-shell lines of another ejecta feature located near the northeastern edge of the remnant, from which we measure redward Doppler velocities of 650 ± 70 ± 60 km s −1 .