The morphology of the ejecta of SN 1987A at 31 years from 1150 to 10000 Å

Abstract

We present spectroscopy of the ejecta of SN 1987A in 2017 and 2018 from the Hubble Space Telescope and the Very Large Telescope, covering the wavelength range between $1150$ and $10000$ Å. At 31 years, this is the first epoch with coverage over the ultraviolet-to-near-infrared range since 1995. We create velocity maps of the ejecta in the H$\alpha$, Mg II $\lambda \lambda 2796,2804$ and [O I] $\lambda \lambda 6302,6366$ (vacuum) emission lines and study their morphology. All three lines have a similar morphology, but Mg II is blueshifted by $\sim$1000 km s${}^{-1}$ relative to the others and stronger in the northwest. We also study the evolution of the line fluxes, finding a brightening by a factor of $\sim$9 since 1999 in Mg II, while the other line fluxes are similar in 1999 and 2018. We discuss implications for the power sources of emission lines at late times: thermal excitation due to heating by the X-rays from the ejecta-ring interaction is found to dominate the ultraviolet Mg II lines, while the infrared Mg II doublet is powered mainly by Ly$\alpha$ fluorescence. The X-ray deposition is calculated based on merger models of SN 1987A. Far-ultraviolet emission lines of H${}_2$ are not detected. Finally, we examine the combined spectrum of recently-discovered hotspots outside the equatorial ring. Their unresolved Balmer emission lines close to zero velocity are consistent with the interaction of fast ejecta and a clumpy, slowly moving outflow. A clump of emission in this spectrum, south of the equatorial ring at $\sim$1500 km s${}^{-1}$, is likely associated with the reverse shock.

19 pages, 17 figures. Accepted for publication in MNRAS

References in corpus (23)

• A distance to the Large Magellanic Cloud that is precise to one per cent
• Three-Dimensional Simulations of Core-Collapse Supernovae: From Shock Revival to Shock Breakout
• CHIANTI - an atomic database for emission lines - Paper XV: Version 9, improvements for the X-ray satellite lines
• A stubbornly large mass of cold dust in the ejecta of Supernova 1987A
• The Triple-Ring Nebula around SN1987A: Fingerprint of a binary merger
• High angular resolution ALMA images of dust and molecules in the SN 1987A ejecta
• X-ray illumination of the ejecta of Supernova 1987A
• Chandra Observes the End of an Era SN 1987A
• The Destruction of the Circumstellar Ring of SN 1987A
• Three-dimensional distribution of ejecta in Supernova 1987A at 10 000 days
• Spectral and morphological analysis of the remnant of Supernova 1987A with ALMA & ATCA
• Matter Mixing in Aspherical Core-collapse Supernovae: Three-dimensional Simulations with Single Star and Binary Merger Progenitor Models for SN 1987A
• Very Deep Inside the SN 1987A Core Ejecta: Molecular Structures Seen in 3D
• Time evolution of the line emission from the inner circumstellar ring of SN 1987A and its hot spots
• Supernova 1987A: 3D Mixing and light curves for explosion models based on binary-merger progenitors
• Indication of a Pulsar Wind Nebula in the hard X-ray emission from SN 1987A
• The matter beyond the ring: the recent evolution of SN 1987A observed by the Hubble Space Telescope
• Thermal Emission and Radioactive Lines, but No Pulsar, in the Broadband X-Ray Spectrum of Supernova 1987A
• Evolution of the Reverse Shock Emission from SNR 1987A
• The Slow Demise of the Long-Lived SN 2005ip
• The Post-impact Evolution of the X-ray Emitting Gas in SNR 1987A Viewed by XMM-Newton
• A 3D view of molecular hydrogen in Supernova 1987A
• Mapping High-velocity H-alpha and Lyman-alpha Emission from Supernova 1987A

Cited by in corpus (6)

• Emission lines due to ionizing radiation from a compact object in the remnant of Supernova 1987A
• JWST NIRSpec observations of Supernova 1987A -- from the inner ejecta to the reverse shock
• Cosmic nucleosynthesis: a multi-messenger challenge
• Mid-infrared imaging of Supernova 1987A
• Polarized radio emission unveils the structure of the pre-supernova circumstellar magnetic field and the radio emission in SN1987A
• Near-infrared evolution of the equatorial ring of SN 1987A