[ITAL]HUBBLE SPACE TELESCOPE[/ITAL][ITAL]Hubble Space Telescope[/ITAL] WFPC2 Imaging of Cassiopeia A

Fesen, Robert A.; Morse, Jon A.; Chevalier, Roger A.; Borkowski, Kazimierz J.; Gerardy, Christopher L.; Lawrence, Stephen S.; Bergh, Sidney van den

doi:10.1086/323539

Cited by 79 publications

(95 citation statements)

References 55 publications

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“…Fesen et al (2001) have observed fast-moving knots (FMKs) in the optical, while Rho et al (2009Rho et al ( , 2012 have detected rovibrational transitions of CO in emission in several small knots located at the RS position. High energy line detection of shocked CO with Herschel confirmed the existence of high-density gas regions in the remnant (Wallström et al 2013).…”

Section: The Reverse Shock Modelsmentioning

confidence: 99%

“…We will then study the dust reprocessing in clumps and the inter-clump medium for various RS models. Presently, we model the non-equilibrium chemistry of the SN ejecta and that of the post-RS gas, by assuming that the processed ejecta material resides in dense, fast-moving knots, as observed by Fesen et al (2001Fesen et al ( , 2006 and Docenko & Sunyaev (2010, hereafter DS10). In Sect.…”

Section: Introductionmentioning

confidence: 99%

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Molecules and dust in Cassiopeia A

Biscaro

Cherchneff

2014

A&A

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Aims. We study the chemistry of the type IIb supernova ejecta, which led to the Cas A supernova remnant, to assess the chemical type and quantity of dust that forms and evolves in the remnant phase. We later model a dense oxygen-rich ejecta knot, which is crossed by the reverse shock in Cas A, to study the evolution of the clump gas phase and the possibility to reform dust clusters in the post-reverse shock gas. Methods. The chemistry is described by a chemical network that includes all possible processes that are efficient at high gas temperatures and densities. The formation of key bimolecular species (e.g., CO and SiO) and dust clusters of silicates, alumina, silica, metal carbides and sulphides, pure metals, and amorphous carbon is considered. A set of stiff, coupled ordinary differential equations is solved for the conditions pertaining to both the SN ejecta and the post-reverse shock gas. Results. We find that the ejecta of type IIb SNe are unable to form large amounts of molecules and molecular clusters that are precursors to dust grains, when compared to their type II-P counterparts, because of their diffuse ejecta. The ejecta gas density needs to be increased by several orders of magnitude to allow for the formation of dust clusters. We show that the chemical composition of the dust clusters that form changes drastically and gains in chemical complexity with increasing gas density. Hence, the ejecta of the Cas A supernova progenitor must have been in the form of dense clumps to account for the dust chemical composition and masses that have been inferred from infrared observations of Cas A. As for the impact of the reverse shock on dense ejecta clumps, we show that the ejecta molecules that are destroyed by the shock reform in the post-reverse shock gas with lower abundances than those of the initial ejecta clump, except for SiO. These molecules include CO, SiS, and O 2 . On the other hand, dust clusters are destroyed by the reverse shock and do not reform in the post-reverse shock gas, even for the highest gas density. These results indicate that the synthesis of dust grains out of the gas phase in the dense knots of Cas A and in other supernova remnants is unlikely.

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Section: The Reverse Shock Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Molecules and dust in Cassiopeia A

Biscaro

Cherchneff

2014

A&A

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“…Although the bright ring is not generally confused by overlapping Doppler components at this spatial resolution (Lawrence et al 1995), high-resolution optical and X-ray images resolve structure out at 0. 2-1 (Hughes et al 2000;Fesen et al 2001), so even without projection effects, some blending of structure is unavoidable. In regions where two or more strong emission components are present along the line of sight, which includes most of the interior emission, the [S iii] line ratio represents the emissionweighted average electron density.…”

Section: Electron Densitymentioning

confidence: 99%

SPITZERSPECTRAL MAPPING OF SUPERNOVA REMNANT CASSIOPEIA A

Smith¹,

Rudnick²,

DeLaney³

et al. 2009

ApJ

114

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We present the global distribution of fine-structure infrared line emission in the Cassiopeia A supernova remnant using data from the Spitzer Space Telescope's infrared spectrograph. We identify emission from ejecta materials in the interior, prior to their encounter with the reverse shock, as well as from the postshock bright ring. The global electron density increases by 100 at the shock to ∼ 10 4 cm −3 , providing evidence for strong radiative cooling. There is also a dramatic change in ionization state at the shock, with the fading of emission from low-ionization interior species like [Si ii] giving way to [S iv] and, at even further distances, highenergy X-rays from hydrogenic silicon. Two compact, crescent-shaped clumps with highly enhanced neon abundance are arranged symmetrically around the central neutron star. These neon crescents are very closely aligned with the "kick" direction of the compact object from the remnant's expansion center, tracing a new axis of explosion asymmetry. They indicate that much of the apparent macroscopic elemental mixing may arise from different compositional layers of ejecta now passing through the reverse shock along different directions.

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“…This large SN rate provides a potential opportunity to investigate the early stages of SNR evolution, since there should be numerous other young SNRs between 100 and 1000 years old present in M83. With a high star formation rate and many massive stars, one might expect many young, massive stars and hence many young core-collapse SNRs, such as Cas A in our Galaxy (see Fesen et al 2001 and references therein) or N132D and 1E 0102À7219 in the Magellanic Clouds (see Blair et al 2000;Gaetz et al 2000), to be present in this galaxy.…”

Section: Introductionmentioning

confidence: 98%

An Optical Survey of Supernova Remnants in M83

Blair

Long

2004

ASTROPHYS J SUPPL S

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Observations of the face-on spiral galaxy M83 ( NGC 5236) performed at the Cerro Tololo Inter-American Observatory in Chile have yielded a catalog of optical supernova remnant (SNR) candidates. These observations were performed with the 4 m Blanco telescope and a prime focus CCD imaging system using narrowband interference filters centered on the light of [S ii], H, [O iii], and red and blue continuum bands. Based on strong relative [S ii]:H emission, 71 emission nebulae have been identified as SNR candidates. Positions and H fluxes of the candidates are presented. Follow-up spectra of 25 of the SNR candidates, also performed at CTIO, have confirmed many of the SNR identifications, although the spectra of a few objects are discrepant, perhaps because of inaccurate aperture placement. In addition, the low mean excitation of M83 H ii regions has allowed a separate search for young oxygen-dominated (core collapse) SNRs similar to Cas A in our Galaxy, using [O iii]:H. This search found a number of the same objects as the [S ii]:H search, indicating that many of these SNRs have shock velocities in excess of 100 km s À1 . However, no bona fide young core-collapse SNRs were detected with this technique, with the possible exception of the independent recovery of SN 1957D, which had been seen previously. We have also attempted to identify optical counterparts for the six historical supernovae that have occurred in M83. Except for SN 1957D, none of the historical supernovae have been detected by this survey. We compare our SNR candidate list against the Chandra X-ray source list of Soria and Wu and identify 15 X-ray sources as likely SNRs, based on positional coincidence within 1 00 . The sources identified have hardness ratios that are soft compared to the general X-ray source population in M83.

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[ITAL]HUBBLE SPACE TELESCOPE[/ITAL][ITAL]Hubble Space Telescope[/ITAL] WFPC2 Imaging of Cassiopeia A

Cited by 79 publications

References 55 publications

Molecules and dust in Cassiopeia A

Molecules and dust in Cassiopeia A

SPITZERSPECTRAL MAPPING OF SUPERNOVA REMNANT CASSIOPEIA A

An Optical Survey of Supernova Remnants in M83

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