Modeling W44 as a Supernova Remnant in a Density Gradient with a Partially Formed Dense Shell and Thermal Conduction in the Hot Interior. I. The Analytical Model

Cox, D. P.; Shelton, R. L.; Maciejewski, Witold; Smith, Randall K.; Plewa, T.; Pawl, Andrew; Rozyczka, M.

doi:10.1086/307781

Cited by 163 publications

(234 citation statements)

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“…The hard component would arise from the hot interior shocked by a fast shock earlier in the evolution of the remnant. Alternatively, a Sedov model invoking thermal conduction would modify the Sedov dynamics, and produce a hot inner component (as was pro-posed for the SNR W44 ; Cox et al 1999). In this scenario, the SNR would be entering its radiative phase and would emit in the infrared.…”

Section: Discussionmentioning

confidence: 99%

A Broadband X‐Ray Study of Supernova Remnant 3C 397

Safi‐Harb

Petre

Arnaud

et al. 2000

ApJ

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We present a broadband imaging and spectral study of the radio-bright supernova remnant (SNR) 3C 397 with ROSAT , ASCA, and RXT E. A bright X-ray spot seen in the HRI image hints at the presence of a pulsar-powered component and gives this SNR a composite X-ray morphology. Combined ROSAT and ASCA imaging shows that the remnant is highly asymmetric, with its X-ray emission peaking at the western lobe. The hard-band images obtained with the ASCA Gas Imaging Spectrometer show that much of the hard X-ray emission arises from the western lobe, associated with the SNR shell, with little hard X-ray emission associated with the central hot spot. The spectrum from 3C 397 is heavily absorbed and dominated by thermal emission with emission lines evident from Mg, Si, S, Ar and Fe. Single-component models fail to describe the X-ray spectrum, and at least two components are required : a soft component characterized by a low temperature and a large ionization timescale, and a hard component required to account for the Fe-K emission line and characterized by a much lower ionization timescale. We use a set of nonequilibrium ionization (NEI) models (Borkowski et al., in preparation), and Ðnd that the Ðtted parameters are robust. The temperatures from the soft and hard components are D0.2 keV and D1.6 keV respectively. The corresponding ionization timescales being the pren 0 t (n 0 shock hydrogen density) are D6 ] 1012 cm~3 s and D6 ] 1010 cm~3 s, respectively. The large of n 0 t the soft component suggests it is approaching ionization equilibrium ; thus it can be Ðt equally well with a collisional equilibrium ionization model. The spectrum obtained with the Proportional Counter Array (PCA) of RXT E is contaminated by emission from the Galactic ridge, with only D15% of the count rate originating from 3C 397 in the 5È15 keV range. The PCA spectrum allowed us to conÐrm the thermal nature of the hard X-ray emission. A third component originating from a pulsar-driven component is possible, but the contamination of the source signal by the Galactic ridge did not allow us to determine its parameters or Ðnd pulsations from any hidden pulsar. We discuss the X-ray spectrum in the light of two scenarios : a young ejecta-dominated remnant of a core-collapse SN, and a middle-aged SNR expanding in a dense ISM. In the Ðrst scenario, the hot component arises from the SNR shell, and the soft component from an ejecta-dominated component. 3C 397 would be a young SNR (a few thousand years old), but intermediate in dynamical age between the young historical shells (like Tycho or Kepler), and those that are well into the Sedov phase of evolution (like Vela). In the second scenario, the soft component represents the blast wave propagating in a dense medium, and the hard component is associated with hot gas encountering a fast shock, or arising from thermal conduction. In this latter scenario, the SNR would be Dtwice as old, and transitioning into the radiative phase. The current picture we present in this paper is marginally consistent with thi...

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Section: Discussionmentioning

confidence: 99%

A Broadband X‐Ray Study of Supernova Remnant 3C 397

Safi‐Harb

Petre

Arnaud

et al. 2000

ApJ

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“…Therefore thermal conduction may play a role in smoothing the temperature distribution. Direct comparison with results obtained by Cox et al (1999) is difficult since their solutions are constructed assuming spherical symmetry which is not the case of G350.0−2.0.…”

Section: The Remnantmentioning

confidence: 99%

“…This class represents about 8 per cent of total Galactic SNR population and about 25 per cent of all Galactic SNRs observed in X-rays (Rho & Petre 1998). Two main scenarios were proposed to explain MM SNRs morphology: the first one is based on effects of thermal conduction processes within the SNR interior (e.g., Cox et al 1999) and the other one -on a cloudlet evaporation (e.g., White & Long 1991) assuming the SNR shock propagation through a cloudy ISM. A fraction of MM SNRs shows enhanced metal abundances (see, e.g., Lazendic & Slane 2006) that is not properly addressed by traditional models.…”

Section: Introductionmentioning

confidence: 99%

XMM–Newtonstudies of the supernova remnant G350.0−2.0

Карпова¹,

Shternin²,

Zyuzin³

et al. 2016

Mon. Not. R. Astron. Soc.

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We report the results of XMM-Newton observations of the Galactic mixed-morphology supernova remnant G350.0−2.0. Diffuse thermal X-ray emission fills the north-western part of the remnant surrounded by radio shell-like structures. We did not detect any X-ray counterpart of the latter structures, but found several bright blobs within the diffuse emission. The X-ray spectrum of the most part of the remnant can be described by a collisionally-ionized plasma model vapec with solar abundances and a temperature of ≈ 0.8 keV. The solar abundances of plasma indicate that the X-ray emission comes from the shocked interstellar material. The overabundance of Fe was found in some of the bright blobs. We also analysed the brightest point-like X-ray source 1RXS J172653.4−382157 projected on the extended emission. Its spectrum is well described by the two-temperature optically thin thermal plasma model mekal typical for cataclysmic variable stars. The cataclysmic variable source nature is supported by the presence of a faint (g ≈ 21) optical source with non-stellar spectral energy distribution at the X-ray position of 1RXS J172653.4−382157. It was detected with the XMM-Newton optical/UV monitor in the U filter and was also found in the archival Hα and optical/near-infrared broadband sky survey images. On the other hand, the X-ray spectrum is also described by the power law plus thermal component model typical for a rotation powered pulsar. Therefore, the pulsar interpretation of the source cannot be excluded. For this source, we derived the upper limit for the pulsed fraction of 27 per cent.

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“…Of these two scenarios, the relic X-ray emission scenario was preferred by Harrus et al (1997) to explain the morphology of W44. One year later, Cox et al (1999); Shelton et al (1999) used a similar scenario as Harrus et al (1997) to model the characteristics of the MMR W44, but added a density gradient for the ISM and thermal conduction. Thermal conduction in the model by Cox et al (1999) smoothes the temperature gradient from the centre to the outer layers, thereby reducing the pressure in the centre.…”

Section: Introductionmentioning

confidence: 99%

A Chandra X-ray study of the mixed-morphology supernova remnant 3C 400.2

Broersen

Vink

2014

Monthly Notices of the Royal Astronomical Society

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We present an analysis of archival Chandra observations of the mixed-morphology remnant 3C400.2. We analysed spectra of different parts of the remnant to observe if the plasma properties provide hints on the origin of the mixed-morphology class. These remnants often show overionization, which is a sign of rapid cooling of the thermal plasma, and super-solar abundances of elements which is a sign of ejecta emission. Our analysis shows that the thermal emission of 3C400.2 can be well explained by a two component non-equilibrium ionization model, of which one component is underionized, has a high temperature (kT ≈ 3.9 keV) and super-solar abundances, while the other component has a much lower temperature (kT ≈ 0.14 keV), solar abundances and shows signs of overionization. The temperature structure, abundance values and density contrast between the different model components suggest that the hot component comes from ejecta plasma, while the cooler component has an interstellar matter origin. This seems to be the first instance of an overionized plasma found in the outer regions of a supernova remnant, whereas the ejecta component of the inner region is underionized. In addition, the non-ionization equilibrium plasma component associated with the ejecta is confined to the central, brighter parts of the remnant, whereas the cooler component is present mostly in the outer regions. Therefore our data can most naturally be explained by an evolutionary scenario in which the outer parts of the remnant are cooling rapidly due to having swept up high density ISM, while the inner parts are very hot and cooling inefficiently due to low density of the plasma. This is also known as the relic X-ray scenario.

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Modeling W44 as a Supernova Remnant in a Density Gradient with a Partially Formed Dense Shell and Thermal Conduction in the Hot Interior. I. The Analytical Model

Cited by 163 publications

References 44 publications

A Broadband X‐Ray Study of Supernova Remnant 3C 397

A Broadband X‐Ray Study of Supernova Remnant 3C 397

XMM–Newtonstudies of the supernova remnant G350.0−2.0

A Chandra X-ray study of the mixed-morphology supernova remnant 3C 400.2

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