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Supernova 1987A offers a unique opportunity to study an evolving supernova inunprecedented detail over several decades. The X-ray emission is dominated byinteractions between the ejecta and the circumstellar medium, primarily theequatorial ring (ER). We analyze 3.3 Ms of NuSTAR data obtained between 2012and 2020, and two decades of XMM-Newton data. Since ${\sim}$2013, the fluxbelow 2 keV has declined, the 3-8 keV flux has increased, but has started toflatten, and the emission above 10 keV has remained nearly constant. Thespectra are well described by a model with three thermal shock components. Twocomponents at 0.3 and 0.9 keV are associated with dense clumps in the ER, and a4 keV component may be a combination of emission from diffuse gas in the ER andthe surrounding low-density H II region. We disfavor models that involvenon-thermal X-ray emission and place constraints on non-thermal components, butcannot firmly exclude an underlying power law. Radioactive lines show a$^{44}$Ti redshift of $670^{+520}_{-380}$ km s$^{-1}$, $^{44}$Ti mass of$1.73_{-0.29}^{+0.27}\times{}10^{-4}$ solar masses, and $^{55}$Fe mass of$<4.2\times{}10^{-4}$ solar masses. The 35-65 keV luminosity limit on thecompact object is $2\times{}10^{34}$ erg s$^{-1}$, and $<15$% of the 10-20 keVflux is pulsed. Considering previous limits, we conclude that there arecurrently no indications of a compact object, aside from a possible hint ofdust heated by a neutron star in recent ALMA images.

Thermal Emission and Radioactive Lines, but No Pulsar, in the Broadband X-Ray Spectrum of Supernova 1987A