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- T Kangas
- Department of Physics, KTH Royal Institute of Technology, The Oskar Klein Centre, AlbaNova, SE-106 91 Stockholm, Sweden
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- C Fransson
- Department of Astronomy, Stockholm University, The Oskar Klein Centre, AlbaNova, SE-106 91 Stockholm, Sweden
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- J Larsson
- Department of Physics, KTH Royal Institute of Technology, The Oskar Klein Centre, AlbaNova, SE-106 91 Stockholm, Sweden
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- K France
- Laboratory for Atmospheric and Space Physics, University of Colorado, 600 UCB, Boulder, CO 80309, USA
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- R A Chevalier
- Department of Astronomy, University of Virginia, PO Box 400325, Charlottesville, VA 22904-4325, USA
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- R P Kirshner
- Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
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- P Lundqvist
- Department of Astronomy, Stockholm University, The Oskar Klein Centre, AlbaNova, SE-106 91 Stockholm, Sweden
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- S Mattila
- Tuorla Observatory, Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
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- J Sollerman
- Department of Astronomy, Stockholm University, The Oskar Klein Centre, AlbaNova, SE-106 91 Stockholm, Sweden
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- V P Utrobin
- NRC ‘Kurchatov Institute’ – Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya St 25, 117218 Moscow, Russia
抄録
<jats:title>ABSTRACT</jats:title> <jats:p>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 $10\, 000$ Å. At 31 yr, 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 α, Mg ii λλ2796, 2804 and [O i] λλ6302, 6366 (vacuum) emission lines and study their morphology. All three lines have a similar morphology, but Mg ii is blueshifted by ∼1000 km s−1 relative to the others and stronger in the north-west. We also study the evolution of the line fluxes, finding a brightening by a factor of ∼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 α fluorescence. The X-ray deposition is calculated based on merger models of SN 1987A. Far-ultraviolet emission lines of H2 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 ∼1500 km s−1, is likely associated with the reverse shock.</jats:p>
収録刊行物
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- Monthly Notices of the Royal Astronomical Society
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Monthly Notices of the Royal Astronomical Society 511 (2), 2977-2993, 2021-12-20
Oxford University Press (OUP)