Radio Supernova 1987A at 843 MHz

Ball, Lewis; Crawford, David F.; Hunstead, R. W.; Klamer, I. J.; McIntyre, V.

doi:10.1086/319056

Cited by 28 publications

(40 citation statements)

References 23 publications

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“…These plots show that the continued increase in flux density observed at 843 MHz by Ball et al (2001) is also observed at higher frequencies. The increase in slope observed at about day 2900 in the MOST data is also seen in the ATCA data ( Figure 1).…”

Section: Evolution Of Radio Flux Densities and Spectral Indexmentioning

confidence: 62%

“…In this paper, we extend the ATCA observational database from 1995 to February 2001 (day 5100) and discuss these results in conjunction with those of Ball et al (2001). The evolution of the radio flux densities is discussed in Section 2.…”

Section: Introductionmentioning

confidence: 82%

“…The increase in slope observed at about day 2900 in the MOST data is also seen in the ATCA data ( Figure 1). Ball et al (2001) stated that the MOST data after day 3000 were well fitted by a linear trend. However, we believe that there is significant evidence for a long-term increase in slope after day 3000 in both the MOST data set and the ATCA data sets, i.e.…”

Section: Evolution Of Radio Flux Densities and Spectral Indexmentioning

confidence: 99%

“…1) or less, and furthermore, many such interactions. Ball et al (2001) and from the ATCA at 1.4, 2.4, 4.8, and 8.6 GHz at five epochs spread through the data set. Values of the spectral index α, where S = ν α and ν is the frequency, found by linear regression, are given on each plot.…”

Section: Evolution Of Radio Flux Densities and Spectral Indexmentioning

confidence: 99%

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Evolution of the Radio Remnant of SN 1987A: 1990-2001

Manchester

Gaensler

Wheaton

et al. 2002

Publ. – Astron. Soc. Aust

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The development of the radio remnant of SN 1987A has been followed using the Australia Telescope Compact Array since its first detection in 1990 August. The remnant has been observed at four frequencies, 1.4, 2.4, 4.8, and 8.6 GHz, at intervals of 4–6 weeks since the first detection. These data are combined with the 843 MHz data set of Ball et al. (2001) obtained at Molonglo Observatory to study the spectral and temporal variations of the emission. These observations show that the remnant continues to increase in brightness, with a larger rate of increase at recent times. They also show that the radio spectrum is becoming flatter, with the spectral index changing from −0.97 to −0.88 over the 11 years. In addition, at roughly yearly intervals since 1992, the remnant has been imaged at 9 GHz using super-resolution techniques to obtain an effective synthesised beamwidth of about 0″.5. The imaging observations confirm the shell morphology of the radio remnant and show that it continues to expand at ˜3000 km s−1. The bright regions of radio emission seen on the limb of the shell do not appear to be related to the optical hot spots which have subsequently appeared in surrounding circumstellar material.

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Section: Evolution Of Radio Flux Densities and Spectral Indexmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 82%

Section: Evolution Of Radio Flux Densities and Spectral Indexmentioning

confidence: 99%

Section: Evolution Of Radio Flux Densities and Spectral Indexmentioning

confidence: 99%

See 2 more Smart Citations

Evolution of the Radio Remnant of SN 1987A: 1990-2001

Manchester

Gaensler

Wheaton

et al. 2002

Publ. – Astron. Soc. Aust

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“…However, the optical hot spots, which are the inward-protruding dense gas shocked by the blast wave (Pun et al 2002;Sugerman et al 2002), show no correlation in position to the radio lobes (Manchester et al 2002). Although the emergence of the optical hot spots coincided with the arrival of the radioproducing shock at those regions ( Ball et al 2001), Manchester et al (2002) indicate that this had little effect on the morphology of the radio remnant.…”

Section: Introduction Sn 1987a In the Largementioning

confidence: 99%

Fourier Modeling of the Radio Torus Surrounding SN 1987A

Gaensler

Staveley‐Smith

et al. 2008

Astrophysical Journal

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We present detailed Fourier modeling of the radio remnant of SN 1987A using high-resolution 9 and 18 GHz data taken with the Australia Telescope Compact Array over the period 1992-2008. We develop a parameterized threedimensional torus model for the expanding radio shell, in which the emission is confined to an inclined equatorial belt; our model also incorporates both a correction for light-travel time effects and an overall east-west gradient in the radio emissivity. By deriving an analytic expression for the two-dimensional Fourier transform of the projected threedimensional brightness distribution, we can fit our spatial model directly to the interferometric visibility data. This provides robust estimates of the radio morphology at each epoch. The best-fit results suggest a constant remnant expansion at 4000 AE 400 km s À1 over the 16 yr period covered by the observations. The model fits also indicate substantial midlatitude emission, extending to AE40 on either side of the equatorial plane. This likely corresponds to the extraplanar structure seen in H and Ly emission from the supernova reverse shock, and broadly supports hydrodynamic models in which the complex circumstellar environment was produced by a progression of interacting winds from the progenitor. Our model quantifies the clear asymmetry seen in the radio images: we find that the eastern half of the radio remnant is consistently $40% brighter than the western half at all epochs, which may result from an asymmetry in the ejecta distribution between these two hemispheres.

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