Spectral and morphological analysis of the remnant of Supernova 1987A with ALMA & ATCA

Abstract

We present a comprehensive spectral and morphological analysis of the remnant of Supernova (SN) 1987A with the Australia Telescope Compact Array (ATCA) and the Atacama Large Millimeter/submillimeter Array (ALMA). The non-thermal and thermal components of the radio emission are investigated in images from 94 to 672 GHz ($\lambda$ 3.2 mm to 450 $\mu$m), with the assistance of a high-resolution 44 GHz synchrotron template from the ATCA, and a dust template from ALMA observations at 672 GHz. An analysis of the emission distribution over the equatorial ring in images from 44 to 345 GHz highlights a gradual decrease of the east-to-west asymmetry ratio with frequency. We attribute this to the shorter synchrotron lifetime at high frequencies. Across the transition from radio to far infrared, both the synchrotron/dust-subtracted images and the spectral energy distribution (SED) suggest additional emission beside the main synchrotron component ($S_{\nu }\propto {\nu }^{-0.73}$) and the thermal component originating from dust grains at $T\sim 22$ K. This excess could be due to free-free flux or emission from grains of colder dust. However, a second flat-spectrum synchrotron component appears to better fit the SED, implying that the emission could be attributed to a pulsar wind nebula (PWN). The residual emission is mainly localised west of the SN site, as the spectral analysis yields $-0.4\lesssim \alpha \lesssim -0.1$ across the western regions, with $\alpha \sim 0$ around the central region. If there is a PWN in the remnant interior, these data suggest that the pulsar may be offset westward from the SN position.

ApJ accepted. 21 pages, emulateapj. References updated

References in corpus (12)

• The ATNF Pulsar Catalogue
• Revised equipartition & minimum energy formula for magnetic field strength estimates from radio synchrotron observations
• Getting Its Kicks: A VLBA Parallax for the Hyperfast Pulsar B1508+55
• The Triple-Ring Nebula around SN1987A: Fingerprint of a binary merger
• X-ray illumination of the ejecta of Supernova 1987A
• Evolutionary Status of SNR 1987A at the Age of Eighteen
• High-resolution radio observations of SNR 1987A at high frequencies
• Fourier Modeling of the Radio Torus Surrounding Supernova 1987A
• Expected gamma-ray emission of supernova remnant SN 1987A
• Magnetic field in supernova remnant SN 1987A
• Searching for a Pulsar in SN1987A
• Fifteen Years of High-Resolution Radio Imaging of Supernova 1987A

Cited by in corpus (17)

• Pulsational Pair-Instability Supernovae
• A stubbornly large mass of cold dust in the ejecta of Supernova 1987A
• High angular resolution ALMA images of dust and molecules in the SN 1987A ejecta
• The Science of the Einstein Telescope
• The ALMA Band 9 receiver - Design, construction, characterization, and first light
• Chandra Observes the End of an Era SN 1987A
• Thermal Emission and Radioactive Lines, but No Pulsar, in the Broadband X-Ray Spectrum of Supernova 1987A
• SN 1986J VLBI. IV. The Nature of the Central Component
• Atacama Compact Array Observations of the Pulsar-Wind Nebula of SNR 0540-69.3
• Latest Evolution of the X-Ray Remnant of SN 1987A: Beyond the Inner Ring
• Mapping High-velocity H-alpha and Lyman-alpha Emission from Supernova 1987A
• The morphology of the ejecta of SN 1987A at 31 years from 1150 to 10000 Å
• On the Possibility of Fast Radio Bursts from Inside Supernovae: The Case of SN 1986J
• Mid-infrared imaging of Supernova 1987A
• Near-infrared evolution of the equatorial ring of SN 1987A
• Titanium hidden in dust
• The Radio Remnant of Supernova 1987A - A Broader View