Mapping High-velocity H? and Ly? Emission from Supernova 1987A

We present new Hubble Space Telescope images of high-velocity H? and Ly? emission in the outer debris of SN 1987 A. The H? images are dominated by emission from hydrogen atoms crossing the reverse shock (RS). For the first time we observe emission from the RS surface well above and below the equatorial?ring (ER), suggesting a bipolar or conical structure perpendicular to the ring plane. Using the H? imaging, we measure the mass flux of hydrogen atoms crossing the RS front, in the velocity intervals (?7500 < Vobs < ?2800 km s?1) and (1000 < Vobs < 7500 km s?1), = 1.2 ? 10?3 M yr?1. We also present the first Ly? imaging of the whole remnant and new Chandra X-ray observations. Comparing the spatial distribution of the Ly? and X-ray emission, we observe that the majority of the high-velocity Ly? emission originates interior to the ER. The observed Ly?/H? photon ratio, ? 17, is significantly higher than the theoretically predicted ratio of ?5 for neutral atoms crossing the RS front. We attribute this excess to Ly? emission produced by X-ray heating of the outer debris. The spatial orientation of the Ly? and X-ray emission suggests that X-ray heating of the outer debris is the dominant Ly? production mechanism in SN 1987 A at this phase in its evolution.