The Re-Acceleration of the Shock Wave in the Radio Remnant of SN 1987A

Abstract

We report on updated radio imaging observations of the radio remnant of Supernova 1987A (SN 1987A) at 9 GHz, taken with the Australia Telescope Compact Array (ATCA), covering a 25-year period (1992-2017). We use Fourier modeling of the supernova remnant to model its morphology, using both a torus model and a ring model, and find both models show an increasing flux density, and have shown a continuing expansion of the remnant. As found in previous studies, we find the torus model most accurately fits our data, and has shown a change in the remnant expansion at Day 9,300 $\pm$210 from 2,300 $\pm$200 km/s to 3,610 $\pm$240 km/s. We have also seen an increase in brightness in the western lobe of the remnant, although the eastern lobe is still the dominant source of emission, unlike what has been observed at contemporary optical and X-ray wavelengths. We expect to observe a reversal in this asymmetry by the year $\sim$2020, and note the south-eastern side of the remnant is now beginning to fade, as has also been seen in optical and X-ray data. Our data indicate that high-latitude emission has been present in the remnant from the earliest stages of the shockwave interacting with the equatorial ring around Day 5,000. However, we find the emission has become increasingly dominated by the low-lying regions by Day 9,300, overlapping with the regions of X-ray emission. We conclude that the shockwave is now leaving the equatorial ring, exiting first from the south-east region of the remnant, and is re-accelerating as it begins to interact with the circumstellar medium beyond the dense inner ring.

arXiv comment22 pages, 14 figures. Accepted to ApJ

References in corpus (32)

• The Australia Telescope Compact Array Broadband Backend (CABB)
• Data analysis recipes: Fitting a model to data
• The Triple-Ring Nebula around SN1987A: Fingerprint of a binary merger
• On the Origin of Radial Magnetic Fields in Young Supernova Remnants
• Long Term Radio Monitoring of SN 1993J
• The asymmetric radio remnant of SN 1987A
• Axisymmetric circumstellar interaction in supernovae
• Supernova 1987A: a Template to Link Supernovae to their Remnants
• Multiple ring nebulae around blue supergiants
• The Three-Dimensional Circumstellar Environment of SN 1987A
• Chandra Observes the End of an Era SN 1987A
• Multi-frequency Radio Measurements of SN 1987A over 22 Years
• Abundances and density structure of the inner circumstellar ring around SN 1987A
• The Destruction of the Circumstellar Ring of SN 1987A
• SN 1993J VLBI (III): The Evolution of the Radio Shell
• Spectral and morphological analysis of the remnant of Supernova 1987A with ALMA & ATCA
• Chandra observations of SN 1987A: the soft X-ray light curve revisited
• High-resolution radio observations of SNR 1987A at high frequencies
• SN1993J VLBI (I): The Center of the Explosion and a Limit on Anisotropic Expansion
• X-ray Evolution of SNR 1987A: The Radial Expansion
• Fourier Modeling of the Radio Torus Surrounding Supernova 1987A
• SN 1986J VLBI. The Evolution and Deceleration of the Complex Source and a Search for a Pulsar Nebula
• Evolution of the Radio Remnant of Supernova 1987A: Morphological Changes from Day 7000
• SN 1986J VLBI: II. The Evolution of the Shell and the Central Source
• Progenitor Model of SN 1987A Based on the Slow Merger Scenario
• Multi-dimensional simulations of the expanding supernova remnant of SN 1987A
• Detection of Linear Polarization in the Radio Remnant of Supernova 1987A
• SN 2014C: VLBI Images of a Supernova Interacting with a Circumstellar Shell
• Imaging the Expanding Shell of SN 2011dh
• Fifteen Years of High-Resolution Radio Imaging of Supernova 1987A
• High Resolution X-ray Imaging of Supernova Remnant 1987A
• SN 1986J VLBI. III. The Central Component Becomes Dominant

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• Spectral Evolution of the X-Ray Remnant of SN 1987A: A High-Resolution $Chandra$ HETG Study
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• Polarized radio emission unveils the structure of the pre-supernova circumstellar magnetic field and the radio emission in SN1987A
• Near-infrared evolution of the equatorial ring of SN 1987A
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