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Cendes et al. 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 the 25-year period
from 1992 to 2017. This monitoring program project is one of the
longest running programs with the ATCA. The supernova remnant
continues to brighten and expand. Cendes et al. try fiting both a
torus model and a ring model to the data, favouring a torus model,
which reveals a change in the remnant expansion in 2013 from about 2,300
km/s to 3,610 km/s. They also see an increase in the brightness of the
western lobe of the remnant, in contrast to contemporary optical and
X-ray observations. The authors predict a reversal in this
asymmetry in several years' time, as the south-eastern side of the
remnant is now beginning to fade. More details are available from
the preprint, with the paper accepted for publication
in the Astrophysical Journal.
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