Zanardo, G, Staveley-Smith, L, Indebetouw, R, Chevalier, RA, Matsuura, M, Gaensler, BM, Barlow, MJ, Fransson, C, Manchester, RN, Baes, M, Kamenetzky, JR, Lakicevic, M, Lundqvist, P, Marcaide, JM, Marti-Vidal, I, Meixner, M, Ng, C-Y, Park, S, Sonneborn, G, Spyromilio, J and van Loon, JT (2014) Spectral and morphological analysis of the remnant of supernova 1987A with Alma and Atca. Astrophysical Journal, 796 (2). ISSN 0004-637X

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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 (λ 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 ν∝ν–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 α lesssim –0.1 across the western regions, with α ~ 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.

Item Type: Article
Additional Information: ©IOP Publishing, American Astronomical Society
Uncontrolled Keywords: ISM: supernova remnants, radiation mechanisms: non-thermal, radiation mechanisms: thermal, radio continuum: general, stars: neutron, supernovae: individual (SN 1987A)
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Faculty of Natural Sciences > School of Physical and Geographical Sciences
Related URLs:
Depositing User: Symplectic
Date Deposited: 14 Jul 2015 10:19
Last Modified: 15 May 2019 14:27

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