The emission of supernova remnants reflects the properties of both the
progenitor supernovae and the surrounding environment. The complex morphology
of the remnants, however, hampers the disentanglement of the two contributions.
Here we aim at identifying the imprint of SN 1987A on the X-ray emission of its
remnant and at constraining the structure of the environment surrounding the
supernova. We performed high-resolution hydrodynamic simulations describing SN
1987A soon after the core-collapse and the following three-dimensional
expansion of its remnant between days 1 and 15000 after the supernova. We
demonstrated that the physical model reproducing the main observables of SN
1987A during the first 250 days of evolution reproduces also the X-ray emission
of the subsequent expanding remnant, thus bridging the gap between supernovae
and supernova remnants. By comparing model results with observations, we
constrained the explosion energy in the range 1.2−1.4×1051~erg and
the envelope mass in the range 15−17M⊙. We found that the shape of
X-ray lightcurves and spectra at early epochs (<15 years) reflects the
structure of outer ejecta: our model reproduces the observations if the
outermost ejecta have a post-explosion radial profile of density approximated
by a power law with index α=−8. At later epochs, the shapes of X-ray
lightcurves and spectra reflect the density structure of the nebula around SN
1987A. This enabled us to ascertain the origin of the multi-thermal X-ray
emission, to disentangle the imprint of the supernova on the remnant emission
from the effects of the remnant interaction with the environment, and to
constrain the pre-supernova structure of the nebula.Comment: 16 pages, 11 Figures; accepted for publication on Ap
