Observations of the remnants of three historical(?) supernovae

Downes, A. J. B.

doi:10.1093/mnras/210.4.845

Cited by 18 publications

(17 citation statements)

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“…We, however, favor an energy index ␣ ϩ 0.5 of 0.8 because on all accounts it seems ␣ = 0.3. Although no direct estimates of the plerionic flux at radio frequencies exist (except at 32 GHz) because it is faint, earlier maps at 20 cm and 6 cm (Green et al 1988;Downes et al 1984;Becker et al 1985) are consistent with a flat average radio spectrum of the plerion out to 32 GHz, ␣ = 0.3.…”

Section: Discussionmentioning

confidence: 92%

“…The high surface brightness of the remnant in both the radio and X-rays is consistent with a young age. Radio observations made with the VLA at 20 cm with angular resolution of 120Љ show emission along a circular shell (Downes 1984; see also Becker, Markert, & Donahue 1985). Green et al (1988) observed G11.2Ϫ0.3 with the VLA at 20 cm and at 6 cm.…”

Section: Introductionmentioning

confidence: 86%

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Detection of a Hard X-Ray Plerion in the Candidate Historical Remnant G11.2−0.3

Vasisht¹,

Aoki²,

Dotani³

et al. 1996

The Astrophysical Journal

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We present the results of a 32 ks Advanced Satellite f or Cosmolog y and Astroph ysics (ASCA) observation of G11.2Ϫ0.3, which is by far the strongest candidate for the remnant of the historical supernova SN 386. A center-brightened, hard, nonthermal X-ray source was found within the remnant, which we interpret to be plerionic emission due to an embedded pulsar. Our observations indicate that the remnant is a member of the class of ''composite'' remnants, as was hinted by previous observations. The central emission is not pulsed down to a detection limit of 110 33 ergs s Ϫ1 . It could be that the putative pulsar is not beamed in our direction. We also argue that the distance and surface brightness of G11.2Ϫ0.3 imply that the remnant is young and very likely to be the counterpart of the supernova observed by the Chinese in A.D. 386, making it the youngest known Galactic composite. The possible similarity between the spectra of G11.2Ϫ0.3 and 3C 58, two of the youngest plerions, is brought out. These spectra are observed to be quite different from that of the Crab, which is very similar in age. Last, we remark that only after a sustained observational effort spanning two decades by various groups is the true nature of G11.2Ϫ0.3 at last clear. To us this has been a valuable lesson that highlights the importance of a detailed multiwavelength effort, with emphasis on high-frequency radio and X-ray spectral observations for proper classification of remnants. The overabundance of pure shell remnants must be an artifact of the lack of such observations and the selection effects that work against the discovery of plerions. Subject headings: ISM: individual (G11.2Ϫ0.3) -supernova remnants

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 86%

Detection of a Hard X-Ray Plerion in the Candidate Historical Remnant G11.2−0.3

Vasisht¹,

Aoki²,

Dotani³

et al. 1996

The Astrophysical Journal

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“…G11.2−0.3 has been identified as a potential historical SNR since at least the first well-resolved imaging observations at radio (VLA, 20 resolution) and X-ray (Einstein HRI) wavelengths (Downes 1984), where it was argued that its high radio surface brightness and symmetrical well-defined shell structure indicated youth. An identification with the CE 386 event was proposed, but an even younger age was also suggested.…”

Section: Introductionmentioning

confidence: 99%

G11.2−0.3: The Young Remnant of a Stripped-Envelope Supernova

Borkowski

Reynolds

Roberts

2016

ApJ

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We present results of a 400-ks Chandra observation of the young shell supernova remnant (SNR) G11.2−0.3, containing a pulsar and pulsar-wind nebula (PWN). We measure a mean expansion rate for the shell since 2000 of 0.0277 ± 0.0018% yr −1 , implying an age between 1400 and 2400 yr, and making G11.2−0.3 one of the youngest core-collapse SNRs in the Galaxy. However, we find very high absorption (A V ∼ 16 m ± 2 m ), confirming near-IR determinations and ruling out a claimed association with the possible historical SN of 386 CE. The PWN shows strong jets and a faint torus within a larger, more diffuse region of radio emission and nonthermal X-rays. Central soft thermal X-ray emission is anticorrelated with the PWN; that, and more detailed morphological evidence, indicates that the reverse shock has already reheated all ejecta and compressed the PWN. The pulsar characteristic energy-loss timescale is well in excess of the remnant age, and we suggest that the bright jets have been produced since the recompression. The relatively pronounced shell and diffuse hard X-ray emission in the interior, enhanced at the inner edge of the shell, indicate that the immediate circumstellar medium into which G11.2−0.3 is expanding was quite anisotropic. We propose a possible origin for G11.2−0.3 in a stripped-envelope progenitor that had lost almost all its envelope mass, in an anisotropic wind or due to binary interaction, leaving a compact core whose fast winds swept previously lost mass into a dense irregular shell, and which exploded as a Type cIIb or Ibc supernova. Subject headings: ISM: individual objects (G11.2−0.3) -ISM: supernova remnants -X-rays: ISM

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“…Clark & Stephenson (1975) give age estimates for both CTB 37A and B of ∼1500 years and claim that there is a possibility that either source could be the remnant of the supernova of AD 393. This claim is further investigated by Downes (1984) who concluded that although such an association is possible, the remnants may in fact be considerably older.…”

Section: Introductionmentioning

confidence: 99%

Chandra and HESS observations of the supernova remnant CTB 37B

Aharonian

Akhperjanian

Almeida

et al. 2008

A&A

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We discovered the >100 GeV γ-ray source, HESS J1713−381, apparently associated with the shell-type supernova remnant (SNR) CTB 37B, using HESS in 2006. In 2007 we performed X-ray follow-up observations with Chandra with the aim of identifying a synchrotron counterpart to the TeV source and/or thermal emission from the SNR shell. These new Chandra data, together with additional TeV data, allow us to investigate the nature of this object in much greater detail than was previously possible. The new X-ray data reveal thermal emission from a ∼4 region in close proximity to the radio shell of CTB 37B. The temperature of this emission implies an age for the remnant of ∼5000 years and an ambient gas density of ∼0.5 cm −3 . Both these estimates are considerably uncertain due to the asymmetry of the SNR and possible modifications of the kinematics due to efficient cosmic ray (CR) acceleration. A bright (≈7 × 10 −13 erg cm −2 s −1 ) and unresolved (<1 ) source (CXOU J171405.7−381031), with a soft (Γ ≈ 3.3) non-thermal spectrum is also detected in coincidence with the radio shell. Absorption indicates a column density consistent with the thermal emission from the shell, suggesting a genuine association rather than a chance alignment. The observed TeV morphology is consistent with an origin in the complete shell of CTB 37B. The lack of diffuse non-thermal X-ray emission suggests an origin of the γ-ray emission via the decay of neutral pions produced in interactions of protons and nuclei, rather than inverse Compton (IC) emission from relativistic electrons.

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Observations of the remnants of three historical(?) supernovae

Cited by 18 publications

References 0 publications

Detection of a Hard X-Ray Plerion in the Candidate Historical Remnant G11.2−0.3

Detection of a Hard X-Ray Plerion in the Candidate Historical Remnant G11.2−0.3

G11.2−0.3: The Young Remnant of a Stripped-Envelope Supernova

Chandra and HESS observations of the supernova remnant CTB 37B

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