Nature of the central ionizing source in SN 1987A

Ascertain the physical nature of the central ionizing source in SN 1987A indicated by the strong [Ar II] 6.985 µm emission, distinguishing among thermal emission from a cooling neutron star, non-thermal emission from a pulsar wind nebula, shock emission from an expending pulsar-wind–nebula bubble, or a combination of these mechanisms.

Background

The MIRI/MRS data reveal a strong point source at 6.9861 µm ([Ar II] 6.9853 µm) at the center of SN 1987A, with additional weaker high-ionization lines. The line properties suggest emission from the explosive oxygen-burning zone and imply an ionizing source consistent with a central neutron star.

Despite this, the authors state that the exact nature of the ionizing source remains unclear, with plausible scenarios including thermal neutron-star emission, a pulsar wind nebula, shocks from an expanding PWN bubble, or combinations thereof. Imaging with filters covering the [Ar II] line could help, but the fundamental identification of the emission mechanism remains an open problem.