Kinetics of the free radical terpolymerization of diethyl maleate with methyl methacrylate and styrene

Braun, Dietrich; Cei, Gustavo

doi:10.1002/macp.1987.021880115

Cited by 31 publications

(36 citation statements)

References 22 publications

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“…They also observe that the center of expansion of the ejecta is offset from the geometrical center of the spherical shell by ∼0.36 pc, indicating that the ejecta are not traveling at the same velocity in all directions with respect to the central compact object. This is consistent with previous results which indicated a non-spherical expansion for the ejecta (e.g., Braun 1987;Willingdale et al 2002). The three-dimensional reconstructions give us a selective "snapshot" of ejecta in the sense that only material that has recently encountered the remnant's reverse shock will emit strongly in the infrared and especially in the optical and X-ray.…”

Section: Previous Three-dimensional Studiessupporting

confidence: 94%

The Three-Dimensional Structure of Interior Ejecta in Cassiopeia a at High Spectral Resolution

Isensee

Rudnick

DeLaney

et al. 2010

ApJ

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We used the Spitzer Space Telescope's Infrared Spectrograph to create a high-resolution spectral map of the central region of the Cassiopeia A (Cas A) supernova remnant, allowing us to make a Doppler reconstruction of its threedimensional structure. The ejecta responsible for this emission have not yet encountered the remnant's reverse shock or the circumstellar medium, making it an ideal laboratory for exploring the dynamics of the supernova explosion itself. We observe that the O, Si, and S ejecta can form both sheet-like structures and filaments. Si and O, which come from different nucleosynthetic layers of the star, are observed to be coincident in velocity space in some regions, and separated by 500 km s −1 or more in others. Ejecta traveling toward us are, on average, ∼900 km s −1 slower than the material traveling away from us. We compare our observations to recent supernova explosion models and find that no single model can simultaneously reproduce all the observed features. However, models of different supernova explosions can collectively produce the observed geometries and structures of the interior emission. We use the results from the models to address the conditions during the supernova explosion, concentrating on asymmetries in the shock structure. We also predict that the back surface of Cas A will begin brightening in ∼30 years, and the front surface in ∼100 years.

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Section: Previous Three-dimensional Studiessupporting

confidence: 94%

The Three-Dimensional Structure of Interior Ejecta in Cassiopeia a at High Spectral Resolution

Isensee

Rudnick

DeLaney

et al. 2010

ApJ

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“…The remnant has been extensively studied in X-rays (Hughes 1999;Rothenflug et al 1994;Decourchelle & Ballet 1994), radio (Dickel et al 1988), optical , but barely in the IR. The only results come from IRAS observations (Dwek et al 1987;Braun 1987;Arendt 1989;Saken et al 1992).…”

Section: Keplermentioning

confidence: 99%

“…The total flux from the remnant integrated over a 8 diameter circle is 1.9 Jy with an uncertainty of ±0.8 Jy; (a non negligible contribution (0.56 Jy) from stars was subtracted from the total flux). The 12 µm IRAS flux was very uncertain, ranging from 1.8 ± 1.8 Jy (Arendt 1989) to 3.07 ± 0.3 Jy (Braun 1987). Figure 4 shows a comparison between the ISOCAM image of Tycho and an H α image of the remnant.…”

Section: Isocam Observationsmentioning

confidence: 99%

Dust in the Tycho, Kepler and Crab supernova remnants

Douvion

Lagage

Césarsky

et al. 2001

A&A

118

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Abstract. SuperNova Remnants (SNR) have been extensively studied in radio, X-rays and optical, but barely in the InfraRed (IR). From IRAS observations, SNR are known to be IR emitters, but the origin of the emission is difficult to assess because of the limited angular and spectral resolution of IRAS observations. ISO follow-up observations of the Cassiopeia-A SNR have shown that the mid-IR radiation from this remnant was dominated by thermal emission from silicate condensates made from SN material. These condensates constitute a probe which can provide unique information about element mixing inside a SN. In this paper, we present ISOCAM observations of the three other young SNR's known in our galaxy: the Kepler SNR, the Tycho SNR and the Crab Nebula. The emission observed from the Kepler SNR is dominated by dust thermal emission. The dust at the origin of the IR emission is circumstellar, not from SN condensates. "Astronomical" silicates, collisionally heated to a temperature of 107 K, can account for both the mid-IR ISO data and the IRAS data. The IR emission from Tycho is probably also emitted by circumstellar or interstellar dust. In order to reproduce both the mid-IR ISO data and the IRAS data, a model with two dust components, one at a temperature of 107 K and the other at 55 K, is needed. The mid-IR emission from the Crab is dominated by synchrotron radiation; no dust is detected.

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“…Bell et al 1975;Tuffs 1986;Braun 1987;Andersen et al 1991;Kassim et al 1995) and most probably also in the X-ray band (Allen et al 1997;Favata et al 1997). Since SNRs are widely suspected to be the main sources of the Galactic cosmic rays (CRs) up to energies of at least 10 15 eV, this youngest Galactic SNR offers an important possibility to test this CR origin hypothesis.…”

Section: Introductionmentioning

confidence: 99%

Gamma-ray emission from Cassiopeia A produced by accelerated cosmic rays

Berezhko¹,

Pühlhofer²,

Völk³

2003

A&A

119

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Abstract. The nonlinear kinetic model of cosmic ray (CR) acceleration in supernova remnants (SNRs) is used to describe the relevant properties of Cassiopeia A (Cas A). In order to reproduce the SNR's observed size, expansion rate and thermal X-ray emission we employ a piecewise homogeneous model for the progenitor's circumstellar medium developed by Borkowski et al. (1996). It consists of a tenuous inner wind bubble, a dense shell of swept-up red supergiant wind material, and a subsequent red supergiant wind region. A quite large SNR interior magnetic field B d ≈ 1 mG is required to give a good fit for the radio and X-ray synchrotron emission. The steep radio spectrum is consistent with efficient proton acceleration which produces a significant shock modification and leads to a steep electron spectrum at energies e < 1 GeV. The calculated integral γ-ray flux from Cas A, F γ ∝ −1 γ , is dominated by π 0 -decay γ-rays due to relativistic protons. It extends up to roughly 30 TeV if CR diffusion is as strong as the Bohm limit. At TeV energies it satisfactorily agrees with the value 5.8 × 10 −13 cm −2 s −1 detected by the HEGRA collaboration.

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Kinetics of the free radical terpolymerization of diethyl maleate with methyl methacrylate and styrene

Cited by 31 publications

References 22 publications

The Three-Dimensional Structure of Interior Ejecta in Cassiopeia a at High Spectral Resolution

The Three-Dimensional Structure of Interior Ejecta in Cassiopeia a at High Spectral Resolution

Dust in the Tycho, Kepler and Crab supernova remnants

Gamma-ray emission from Cassiopeia A produced by accelerated cosmic rays

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