Shell Shock and Cloud Shock: Results from Spatially Resolved X‐Ray Spectroscopy with<i>Chandra</i>in the Cygnus Loop

Levenson, N. A.; Graham, James R.; Walters, Julie

doi:10.1086/341802

Cited by 36 publications

(38 citation statements)

References 26 publications

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“…They found that, as a result of the interaction, the blast wave diffracts around the cloud and reestablishes ahead of it, in agreement with the observations of Fesen et al (1992). Besides, X-ray ROSAT observations (Levenson et al 1997(Levenson et al , 2002 show an indentation at this region of the Cygnus Loop followed by a compact bright knot interior to the shell, similarly to what is observed in Puppis A.…”

Section: Resultssupporting

confidence: 75%

High-resolution CO observations towards the bright eastern knot of the SNR Puppis A

Paron

Dubner

Reynoso

et al. 2008

A&A

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Aims. This paper reports molecular observations towards the bright eastern knot (BEK) in the SNR Puppis A, a feature where radio and X-ray studies suggest that the shock front is interacting with a dense molecular clump. Methods. We performed high-resolution millimetric observations towards the BEK of Puppis A using the SEST telescope in the 12 CO J = 1-0 and 2-1 lines (beams of 45 and 23 , respectively). More extended, lower angular resolution 12 CO J = 1-0 observations taken from NANTEN archival data were also analyzed to obtain a complete picture. Results. In the velocity range near 16 km s −1 , which is the Puppis A systemic velocity, our study revealed two important properties: (i) no dense molecular gas is detected immediately adjacent to the eastern border of the BEK and (ii) the molecular clump detected very close to the radiocontinuum maximum is probably located in the foreground along the line of sight and has not yet been reached by the SNR shock front. We propose two possible scenarios for explaining the absence of molecular emission eastwards of the BEK border of Puppis A. Either the shock front has completely engulfed and destroyed a molecular clump or the shock front is interacting with part of a larger cloud, and we do not detect CO emission immediately beyond it because the molecules have been dissociated by photodissociation and by reactions with photoionized material due to the radiative precursor.

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Section: Resultssupporting

confidence: 75%

High-resolution CO observations towards the bright eastern knot of the SNR Puppis A

Paron

Dubner

Reynoso

et al. 2008

A&A

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“…While the transmitted shock is slowed significantly as it moves into the dense shell, the reflected shock travels back through the still expanding ejecta, further heating the already shocked gas. Such a reflected shock-heating scenario has been used to explain the observed morphology at shock-cloud interaction regions in the Cygnus Loop (Levenson et al 2002).…”

Section: Thermalmentioning

confidence: 99%

Multi-frequency study of the newly confirmed supernova remnant MCSNR J0512−6707 in the Large Magellanic Cloud

Kavanagh

Sasaki

Bozzetto

et al. 2015

A&A

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Aims. We present a multi-frequency study of the supernova remnant MCSNR J0512−6707 in the Large Magellanic Cloud. Methods. We used new data from XMM-Newton to characterise the X-ray emission and data from the Australian Telescope Compact Array, the Magellanic Cloud Emission Line Survey, and Spitzer to gain a picture of the environment into which the remnant is expanding. We performed a morphological study, determined radio polarisation and magnetic field orientation, and performed an X-ray spectral analysis. Results. We estimated the remnant's size to be 24.9 (±1.5) × 21.9 (±1.5) pc, with the major axis rotated ∼29 • east of north. Radio polarisation images at 3 cm and 6 cm indicate a higher degree of polarisation in the northwest and southeast tangentially oriented to the SNR shock front, indicative of an SNR compressing the magnetic field threading the interstellar medium. The X-ray spectrum is unusual as it requires a soft (∼0.2 keV) collisional ionisation equilibrium thermal plasma of interstellar medium abundance, in addition to a harder component. Using our fit results and the Sedov dynamical model, we showed that the thermal emission is not consistent with a Sedov remnant. We suggested that the thermal X-rays can be explained by MCSNR J0512−6707 having initially evolved into a wind-blown cavity and is now interacting with the surrounding dense shell. The origin of the hard component remains unclear. We could not determine the supernova type from the X-ray spectrum. Indirect evidence for the type is found in the study of the local stellar population and star formation history in the literature, which suggests a core-collapse origin. Conclusions. MCSNR J0512−6707 likely resulted from the core-collapse of high mass progenitor which carved a low density cavity into its surrounding medium, with the soft X-rays resulting from the impact of the blast wave with the surrounding shell. The unusual hard X-ray component requires deeper and higher spatial resolution radio and X-ray observations to confirm its origin.

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“…Optical, UV and X-ray observations of SNRs show that the SN-generated shock waves travel through and interact with the denser clouds they encounter (e.g. Bocchino et al 2000;Levenson et al 2002;Patnaude et al 2002;Nichols & Slavin 2004;Levenson & Graham 2005;Miceli et al 2005), generating transmitted and reflected (bow) shocks, which, in turn, interact with each other (e.g. McKee & Cowie 1975;White & Long 1991;Poludnenko et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Crushing of interstellar gas clouds in supernova remnants

Orlando¹,

Peres

Reale

et al. 2005

A&A

112

148

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We model the hydrodynamic interaction of a shock wave of an evolved supernova remnant with a small interstellar gas cloud like the ones observed in the Cygnus loop and in the Vela SNR. We investigate the interplay between radiative cooling and thermal conduction during cloud evolution and their effect on the mass and energy exchange between the cloud and the surrounding medium. Through the study of two cases characterized by different Mach numbers of the primary shock (M = 30 and 50, corresponding to a post-shock temperature T ≈ 1.7 × 10 6 K and ≈4.7 × 10 6 K, respectively), we explore two very different physical regimes: for M = 30, the radiative losses dominate the evolution of the shocked cloud which fragments into cold, dense, and compact filaments surrounded by a hot corona which is ablated by the thermal conduction; instead, for M = 50, the thermal conduction dominates the evolution of the shocked cloud, which evaporates in a few dynamical time-scales. In both cases we find that the thermal conduction is very effective in suppressing the hydrodynamic instabilities that would develop at the cloud boundaries.

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Shell Shock and Cloud Shock: Results from Spatially Resolved X‐Ray Spectroscopy withChandrain the Cygnus Loop

Cited by 36 publications

References 26 publications

High-resolution CO observations towards the bright eastern knot of the SNR Puppis A

High-resolution CO observations towards the bright eastern knot of the SNR Puppis A

Multi-frequency study of the newly confirmed supernova remnant MCSNR J0512−6707 in the Large Magellanic Cloud

Crushing of interstellar gas clouds in supernova remnants

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