Observing Supernova 1987A with the Refurbished Hubble Space Telescope
astro-ph.CO
/ Authors
Kevin France, Richard McCray, Kevin Heng, Robert Kirshner, Peter Challis, Patrice Bouchet, Arlin Crotts, Eli Dwek, Claes Fransson, Peter Garnavich
and 11 more authors
Josefin Larsson, Stephen Lawrence, Peter Lundqvist, Nino Panagia, Chun Pun, Nathan Smith, Jesper Sollerman, George Sonneborn, John Stocke, Lifan Wang, Craig Wheeler
/ Abstract
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~λλ1239,1243 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.