Mapping High-velocity H-alpha and Lyman-alpha Emission from Supernova 1987A

Abstract

We present new {\it Hubble Space Telescope} images of high-velocity H-$\alpha$ and Lyman-$\alpha$ emission in the outer debris of SN~1987A. The H-$\alpha$ images are dominated by emission from hydrogen atoms crossing the reverse shock. For the first time we observe emission from the reverse shock surface well above and below the equatorial ring, suggesting a bipolar or conical structure perpendicular to the ring plane. Using the H$\alpha$ imaging, we measure the mass flux of hydrogen atoms crossing the reverse shock front, in the velocity intervals ($-$7,500~$<$~$V_{obs}$~$<$~$-$2,800 km s${}^{-1}$) and (1,000~$<$~$V_{obs}$~$<$~7,500 km s${}^{-1}$), $\dot{M_H}$ = 1.2~$\times$~10${}^{-3}$ M${}_{\odot }$ yr${}^{-1}$. We also present the first Lyman-$\alpha$ imaging of the whole remnant and new $Chandra$ X-ray observations. Comparing the spatial distribution of the Lyman-$\alpha$ and X-ray emission, we observe that the majority of the high-velocity Lyman-$\alpha$ emission originates interior to the equatorial ring. The observed Lyman-$\alpha$/H-$\alpha$ photon ratio, $⟨$$R(L\alpha /H\alpha )$$⟩$ $\approx$~17, is significantly higher than the theoretically predicted ratio of $\approx$ 5 for neutral atoms crossing the reverse shock front. We attribute this excess to Lyman-$\alpha$ emission produced by X-ray heating of the outer debris. The spatial orientation of the Lyman-$\alpha$ and X-ray emission suggests that X-ray heating of the outer debris is the dominant Lyman-$\alpha$ production mechanism in SN 1987A at this phase in its evolution.

6 pages, 5 figures. ApJL - accepted

References in corpus (7)

• The Triple-Ring Nebula around SN1987A: Fingerprint of a binary merger
• Discovery of a nearby twin of SN1987A's nebula around the luminous blue variable HD168625: Was Sk--69 202 an LBV?
• X-ray illumination of the ejecta of Supernova 1987A
• Balmer-Dominated Shocks Revisited
• Spectral and morphological analysis of the remnant of Supernova 1987A with ALMA & ATCA
• Chandra LETG Observations of Supernova Remnant 1987A
• Evolution of the Reverse Shock Emission from SNR 1987A

Cited by in corpus (7)

• Endurance of SN 2005ip after a decade: X-rays, radio, and H-alpha like SN 1988Z require long-lived pre-supernova mass loss
• The Destruction of the Circumstellar Ring of SN 1987A
• Three-dimensional distribution of ejecta in Supernova 1987A at 10 000 days
• The matter beyond the ring: the recent evolution of SN 1987A observed by the Hubble Space Telescope
• JWST NIRSpec observations of Supernova 1987A -- from the inner ejecta to the reverse shock
• The morphology of the ejecta of SN 1987A at 31 years from 1150 to 10000 Å
• Energy Conservation in the thin layer approximation: II. The asymmetric classic case for supernovae remnants