Jacobus Van Loon j.t.van.loon@keele.ac.uk
Spectral and morphological analysis of the remnant of supernova 1987A with Alma and Atca
Van Loon
Authors
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 (? 3.2 mm to 450 µm), 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 ???–0.73) and the thermal component originating from dust grains at T ~ 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 localized west of the SN site, as the spectral analysis yields –0.4 lesssim a lesssim –0.1 across the western regions, with a ~ 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.
Acceptance Date | Sep 26, 2014 |
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Publication Date | Nov 10, 2014 |
Journal | Astrophysical Journal |
Print ISSN | 0004-637X |
Publisher | American Astronomical Society |
DOI | https://doi.org/10.1088/0004-637X/796/2/82 |
Keywords | ISM: supernova remnants, radiation mechanisms: non-thermal, radiation mechanisms: thermal, radio continuum: general, stars: neutron, supernovae: individual (SN 1987A) |
Publisher URL | https://doi.org/10.1088/0004-637X/796/2/82 |
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Publisher Licence URL
https://creativecommons.org/licenses/by/4.0/
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