A Decade-Baseline Study of the Plasma States of Ejecta Knots in Cassiopeia A

Rutherford, John; Dewey, Daniel; Figueroa‐Feliciano, E.; Heine, Sarah N. T.; Bastien, Fabienne A.; Sato, Kosuke; Canizares, C. R.

doi:10.1088/0004-637x/769/1/64

Cited by 14 publications

(18 citation statements)

References 34 publications

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“…As the youngest CC SNR known in the Milky Way, Cas A's emission is ejecta-dominated (Hwang & Laming 2012;Rutherford et al 2013), and thus its morphology reflects the asymmetries of the explosion.…”

Section: Resultsmentioning

confidence: 99%

“…Studies of light echoes from the explosion have revealed that Cas A was produced by an asymmetric Type IIb supernova with variations in ejecta velocities of ≈ 4000 km s −1 (Rest et al 2011). Hwang & Laming (2012) and Rutherford et al (2013) performed spectral analysis of several regions in Cas A using Chandra ACIS observations, and modeled the data as an absorbed, NEI plasma. They found temperatures ranging from kT ≈ 1−3 keV and an average column density of N H ≈ 1.3×10 22 cm −2 .…”

Section: Properties Of the Snrsmentioning

confidence: 99%

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Comparing Neutron Star Kicks to Supernova Remnant Asymmetries

Holland-Ashford

Lopez

Auchettl

et al. 2017

ApJ

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Supernova explosions are inherently asymmetric and can accelerate new-born neutron stars (NSs) to hundreds of km s −1 . Two prevailing theories to explain NS kicks are ejecta asymmetries (e.g., conservation of momentum between NS and ejecta) and anisotropic neutrino emission. Observations of supernova remnants (SNRs) can give us insights into the mechanism that generates these NS kicks. In this paper, we investigate the relationship between NS kick velocities and the X-ray morphologies of 18 SNRs observed with the Chandra X-ray Observatory and the Röntgen Satellite (ROSAT). We measure SNR asymmetries using the power-ratio method (a multipole expansion technique), focusing on the dipole, quadrupole, and octupole power-ratios. Our results show no correlation between the magnitude of the power-ratios and NS kick velocities, but we find that for Cas A and G292.0+1.8, whose emission traces the ejecta distribution, their NSs are preferentially moving opposite to the bulk of the X-ray emission. In addition, we find a similar result for PKS 1209-51, CTB 109, and Puppis A; however their emission is dominated by circumstellar/interstellar material, so their asymmetries may not reflect their ejecta distributions. Our results are consistent with the theory that NS kicks are a consequence of ejecta asymmetries as opposed to anisotropic neutrino emission. In the future, additional observations to measure NS proper motions within ejecta-dominated SNRs are necessary to constrain robustly the NS kick mechanism.

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Section: Resultsmentioning

confidence: 99%

Section: Properties Of the Snrsmentioning

confidence: 99%

Comparing Neutron Star Kicks to Supernova Remnant Asymmetries

Holland-Ashford

Lopez

Auchettl

et al. 2017

ApJ

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“…Helder & Vink (2008) estimated that the fraction of non-thermal component is ∼ 54 % in the 4.2-6 keV band. In the further lower energy band (1-3 keV), no significant X-ray variability in the soft X-ray band (1-3 keV) has been found (e.g., Patnaude et al 2011;Rutherford et al 2013). However, we note the possibility that the 4.2-6 keV and the 1-3 keV band emission may originate from different plasma.…”

Section: Introductionmentioning

confidence: 98%

Multi-year X-Ray Variations of Iron-K and Continuum Emissions in the Young Supernova Remnant Cassiopeia A

Sato

Maeda

Bamba

et al. 2017

ApJ

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We found simultaneous decrease of Fe-K line and 4.2-6 keV continuum of Cassiopeia A with the monitoring data taken by Chandra in 2000-2013. The flux change rates in the whole remnant are −0.65±0.02 % yr −1 in the 4.2-6.0 keV continuum and −0.6±0.1 % yr −1 in the Fe-K. In the eastern region where the thermal emission is considered to dominate, the variations show the largest values: −1.03±0.05 % yr −1 (4.2-6 keV band) and −0.6±0.1 % yr −1 (Fe-K line). In this region, the time evolution of the emission measure and the temperature have a decreasing trend. This could be interpreted as the adiabatic cooling with the expansion of m = 0.66. On the other hand, in the non-thermal emission dominated regions, the variations of the 4.2-6 keV continuum show the smaller rates: −0.60±0.04 % yr −1 in the southwestern region, −0.46±0.05 % yr −1 in the inner region and +0.00±0.07 % yr −1 in the forward shock region. In particular, the flux does not show significant change in the forward shock region. These results imply that a strong braking in the shock velocity has not been occurring in Cassiopeia A (< 5 km s −1 yr −1 ). All of our results support that the X-ray flux decay in the remnant is mainly caused by the thermal components.

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“…Since Cas A has complex structured knots and require reliable spectral analysis, in the Chandra studies [33,34,35], the X-ray background emission of Cas A observations was selected carefully from emission-free regions for the spectral analysis but no background estimation method was indicated.…”

Section: Cas Amentioning

confidence: 99%

The effects of X-ray background on the X-ray emission from the Galactic supernova remnants

Cesur¹,

Sezer²,

Hüdaverdi³

2018

Turk J Phys

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We present the results of an X-ray background emission study of the well-known Galactic supernova remnants (SNRs) Cas A, RCW 86, RX J1713.7 − 3946, and SN 1006 by using the archival Chandra and XMM-Newton X-ray Observatories data. With the advent of detector technologies and increased capability of the spectral resolutions, accurate background modelling for the extended sources, such as SNRs, is getting crucial at the modelling step since it might be effective on estimating the physical parameters of the plasma. For this purpose, we concentrate on the background emission spectral modelling by investigating its spectral parameters and components. Hence, the results of the modelled background spectra of these four SNRs are presented by using the combination of thermal and nonthermal emission models properly to the background components.

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A Decade-Baseline Study of the Plasma States of Ejecta Knots in Cassiopeia A

Cited by 14 publications

References 34 publications

Comparing Neutron Star Kicks to Supernova Remnant Asymmetries

Comparing Neutron Star Kicks to Supernova Remnant Asymmetries

Multi-year X-Ray Variations of Iron-K and Continuum Emissions in the Young Supernova Remnant Cassiopeia A

The effects of X-ray background on the X-ray emission from the Galactic supernova remnants

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