Spectral and Morphological Analysis of the Remnant of Supernova 1987A with ALMA and ATCA
Artikel i vetenskaplig tidskrift, 2014

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 proportional to nu(-0.73)) and the thermal component originating from dust grains at T similar to 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 less than or similar to alpha less than or similar to -0.1 across the western regions, with alpha similar to 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.

radiation mechanisms: non-thermal

ISM: supernova remnants

stars: neutron

supernovae: individual (SN 1987A)

radio continuum: general

radiation mechanisms: thermal


G. Zanardo

University of Western Australia

L. Staveley-Smith

University of Western Australia

Centre of Excellence for All-sky Astrophysics (CAASTRO

R. Indebetouw

University of Virginia

National Radio Astronomy Observatory

R. Chevalier

University of Virginia

M. Matsuura

University College London (UCL)

B. Gaensler

Centre of Excellence for All-sky Astrophysics (CAASTRO

The University of Sydney

M. J. Barlow

University College London (UCL)

C. Fransson

Stockholms universitet

R. N. Manchester

Australia Telescope National Facility

Maarten Baes

Universiteit Gent

J. Kamenetzky

University of Arizona

M. Lakicevic

Keele University

P. Lundqvist

Stockholms universitet

J. M. Marcaide

Donostia International Physics Center

Universitat de Valencia

Ivan Marti-Vidal

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

M. Meixner

Johns Hopkins University

Space Telescope Science Institute (STScI)

C. Y. Ng

The University of Hong Kong

S. Park

University of Texas at Arlington

G. Sonneborn

NASA Goddard Space Flight Center

J. Spyromilio

European Southern Observatory (ESO)

J. T. van Loon

Keele University

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 796 Art. no. 82- 82


Astronomi, astrofysik och kosmologi