Astronomy and Astrophysics – Astrophysics
Scientific paper
2001-07-16
Astronomy and Astrophysics
Astrophysics
10 pages, 11 figures, submitted to Astronomy and Astrophysics
Scientific paper
10.1051/0004-6361:20011614
A detailed X-ray spectral analysis of Cas A using a deep exposure from the EPIC-MOS cameras on-board XMM-Newton is presented. Spectral fitting was performed on a 15x15 grid of 20"x20" pixels using a two component non-equilibrium ionisation model (NEI) giving maps of ionisation age, temperature, interstellar column density, abundances and Doppler velocities. The abundances of Si, S, Ar and Ca are strongly correlated. The abundance ratios are consistent with the nucleosynthesis yield from the collapse of a 12 Msun progenitor. The abundance ratios Ne/Si, Mg/Si, Fe/Si and Ni/Si are very variable and distinctly different from S/Si, Ar/Si and Ca/Si, in line with the current explosive nucleosynthesis models. The ionisation age and temperature of both NEI components varies considerably over the remnant. Accurate determination of these parameters yield reliable Doppler velocities for both components. The data are consistent with a plasma velocity of 2600 km/s at the shock radius of 153" implying a primary shock velocity of 4000+/-500 km/s. The Si-K and S-K line emission from the cool component is confined to a relatively narrow shell with radius 100-150". This component is almost certainly ejecta material which has been heated by a combination of the reverse shock and heating of ejecta clumps as they plough through the medium which has been pre-heated by the primary shock. The Fe-K line emission is expanding faster and spans a radius range 110-170". The bulk of the Fe emission is confined to two large clumps and it is likely that these too are the result of ablation from ejecta bullets rather swept up circumstellar medium.
Bleeker Johan A. M.
Kaastra Jelle S.
van der Heyden K. J.
Vink Jacco
Willingale Richard
No associations
LandOfFree
X-ray spectral imaging and Doppler mapping of Cassiopeia A does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with X-ray spectral imaging and Doppler mapping of Cassiopeia A, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-ray spectral imaging and Doppler mapping of Cassiopeia A will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-472526