Observing Supernova 1987A with the Refurbished Hubble Space Telescope
  Observations with the Hubble Space Telescope (HST), conducted since 1990, now
offer an unprecedented glimpse into fast astrophysical shocks in the young
remnant of supernova 1987A. Comparing observations taken in 2010 using the
refurbished instruments on HST with data taken in 2004, just before the Space
Telescope Imaging Spectrograph failed, we find that the Ly-a and H-a lines from
shock emission continue to brighten, while their maximum velocities continue to
decrease. We observe broad blueshifted Ly-a, which we attribute to resonant
scattering of photons emitted from hotspots on the equatorial ring. We also
detect NV~\lambda\lambda 1239,1243 A line emission, but only to the red of
Ly-A. The profiles of the NV lines differ markedly from that of H-a, suggesting
that the N^{4+} ions are scattered and accelerated by turbulent electromagnetic
fields that isotropize the ions in the collisionless shock.
