Discovery of Outlying High-Velocity Oxygen-Rich Ejecta in Cassiopeia A
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Fesen, Robert A; Hammell, Molly; Morse, Jon; Chevalier, Roger A; Borkowski, Kazimierz J; Dopita, Michael; Gerardy, Christopher L; Lawrence, Stephen S; Raymond, John C; van den Bergh, Sidney
Description
Analysis of broadband HST ACS and WFPC2 images of the young Galactic supernova remnant Cassiopeia A reveals a far larger population of outlying, high-velocity knots of ejecta with a broader range of chemical properties than previously suspected. In this paper, we concentrate on a ≃ 1.5 arcmin2 region located along the eastern limb of the remnant where we identify three main classes of outer ejecta: (1) knots dominated by [N II] λλ6548, 6583 emission, (2) knots dominated by oxygen emission...[Show more]
dc.contributor.author | Fesen, Robert A | |
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dc.contributor.author | Hammell, Molly | |
dc.contributor.author | Morse, Jon | |
dc.contributor.author | Chevalier, Roger A | |
dc.contributor.author | Borkowski, Kazimierz J | |
dc.contributor.author | Dopita, Michael | |
dc.contributor.author | Gerardy, Christopher L | |
dc.contributor.author | Lawrence, Stephen S | |
dc.contributor.author | Raymond, John C | |
dc.contributor.author | van den Bergh, Sidney | |
dc.date.accessioned | 2015-12-08T22:19:25Z | |
dc.identifier.issn | 0004-637X | |
dc.identifier.uri | http://hdl.handle.net/1885/31556 | |
dc.description.abstract | Analysis of broadband HST ACS and WFPC2 images of the young Galactic supernova remnant Cassiopeia A reveals a far larger population of outlying, high-velocity knots of ejecta with a broader range of chemical properties than previously suspected. In this paper, we concentrate on a ≃ 1.5 arcmin2 region located along the eastern limb of the remnant where we identify three main classes of outer ejecta: (1) knots dominated by [N II] λλ6548, 6583 emission, (2) knots dominated by oxygen emission lines, especially [O II] λλ7319, 7330, and (3) knots with emission-line strengths similar to the [S II]-strong fast-moving knot (FMK) ejecta commonly seen in the main emission shell. Mean transverse velocities derived from observed proper motion for N-rich, O-rich, and FMK-like knots identified in this region were found to be 8100, 7900, and 7600 km s-1, respectively. The discovery of a significant population of O-rich ejecta situated between the suspected N-rich outer photospheric layer and S-rich FMK-like ejecta suggests that the progenitor's chemical layers were not completely disrupted by the supernova explosion outside of the remnant's northeast and southwest high-velocity "jet" regions. In addition, we find the majority of O-rich outer ejecta at projected locations out beyond the remnant's fastest moving Fe-rich X-ray emission material seen in Chandra and XMM-Newton data along the eastern limb, suggesting that penetration of Fe-rich material up through the S- and Si-rich mantle did not extend past the progenitor's N- or O-rich outer layers for this section of the remnant. | |
dc.publisher | IOP Publishing | |
dc.source | Astrophysical Journal, The | |
dc.subject | Keywords: ISM: abundances; ISM: individual (Cassiopeia A); ISM: kinematics and dynamics; Supernova remnants | |
dc.title | Discovery of Outlying High-Velocity Oxygen-Rich Ejecta in Cassiopeia A | |
dc.type | Journal article | |
local.description.notes | Imported from ARIES | |
local.identifier.citationvolume | 636 | |
dc.date.issued | 2006 | |
local.identifier.absfor | 020110 - Stellar Astronomy and Planetary Systems | |
local.identifier.ariespublication | u4114753xPUB84 | |
local.type.status | Published Version | |
local.contributor.affiliation | Fesen, Robert A, Dartmouth College | |
local.contributor.affiliation | Hammell, Molly, Dartmouth College | |
local.contributor.affiliation | Morse, Jon, Arizona State University | |
local.contributor.affiliation | Chevalier, Roger A, University of Virginia | |
local.contributor.affiliation | Borkowski, Kazimierz J, North Carolina State University | |
local.contributor.affiliation | Dopita, Michael, College of Physical and Mathematical Sciences, ANU | |
local.contributor.affiliation | Gerardy, Christopher L, Imperial College London | |
local.contributor.affiliation | Lawrence, Stephen S, Hofstra University | |
local.contributor.affiliation | Raymond, John C, Harvard-Smithsonian Centre for Astrophysics | |
local.contributor.affiliation | van den Bergh, Sidney, Herzberg Institute of Astrophysics | |
local.description.embargo | 2037-12-31 | |
local.bibliographicCitation.startpage | 859 | |
local.bibliographicCitation.lastpage | 872 | |
local.identifier.doi | 10.1086/498092 | |
dc.date.updated | 2015-12-08T08:21:58Z | |
local.identifier.scopusID | 2-s2.0-32044470954 | |
Collections | ANU Research Publications |
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