Late-time Optical and X-Ray Emission Evolution of the Oxygen-rich SN 1996cr
When the ejecta of a supernova (SN) interact with the progenitor star's circumstellar environment, a strong shock is driven back into the ejecta, causing the material to become bright optically and in X-rays. Most notably, as the shock traverses the H-rich envelope, it begins to interact with m...
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2025-01-01
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| author | Daniel Patnaude Kathryn E. Weil Robert A. Fesen Dan Milisavljevic Ralph P. Kraft |
| author_facet | Daniel Patnaude Kathryn E. Weil Robert A. Fesen Dan Milisavljevic Ralph P. Kraft |
| author_sort | Daniel Patnaude |
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| description | When the ejecta of a supernova (SN) interact with the progenitor star's circumstellar environment, a strong shock is driven back into the ejecta, causing the material to become bright optically and in X-rays. Most notably, as the shock traverses the H-rich envelope, it begins to interact with metal-rich material. Thus, continued monitoring of bright and nearby SNe provides valuable clues about both the progenitor structure and its pre-SN evolution. Here we present late-time, multiepoch optical and Chandra X-ray spectra of the core-collapse SN, SN 1996cr. Magellan IMACS optical spectra taken in 2017 July and 2021 August show a very different spectrum from that seen in 2006 with broad, double-peaked optical emission lines of oxygen, argon, and sulfur with expansion velocities of ±4500 km s ^−1 . Redshifted emission components are considerably fainter compared to the blueshifted components, presumably due to internal extinction from dust in the SN ejecta. Broad ±2400 km s ^−1 H α is also seen, which we infer is shocked progenitor pre-SN, mass-loss, H-rich material. Chandra data indicate a slow but steady decline in the overall X-ray luminosity, suggesting that the forward shock has broken through any circumstellar shell or torus, which is inferred from prior deep Chandra ACIS-S/HETG observations. The X-ray properties are consistent with what is expected from a shock breaking out into a lower-density environment. Though originally identified as a Type IIn SN, based upon late-time optical emission-line spectra, we argue that the SN 1996cr progenitor was partially or highly stripped, suggesting a Type IIb/Ib SN. |
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| institution | Kabale University |
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| series | The Astrophysical Journal |
| spelling | doaj-art-56450522f7e4430c9fb334398d3d85962025-02-05T14:08:59ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198018210.3847/1538-4357/ada15bLate-time Optical and X-Ray Emission Evolution of the Oxygen-rich SN 1996crDaniel Patnaude0https://orcid.org/0000-0002-7507-8115Kathryn E. Weil1https://orcid.org/0000-0002-8360-0831Robert A. Fesen2https://orcid.org/0000-0003-3829-2056Dan Milisavljevic3https://orcid.org/0000-0002-0763-3885Ralph P. Kraft4https://orcid.org/0000-0002-0765-0511Smithsonian Astrophysical Observatory , 60 Garden Street, Cambridge, MA 02138, USASmithsonian Astrophysical Observatory , 60 Garden Street, Cambridge, MA 02138, USA; Department of Physics and Astronomy, Dartmouth College , 6127 Wilder Lab, Hanover, NH 03755, USA; Department of Physics and Astronomy, Purdue University , 525 Northwestern Avenue, West Lafayette, IN 47907, USADepartment of Physics and Astronomy, Dartmouth College , 6127 Wilder Lab, Hanover, NH 03755, USADepartment of Physics and Astronomy, Purdue University , 525 Northwestern Avenue, West Lafayette, IN 47907, USA; Integrative Data Science Initiative, Purdue University , West Lafayette, IN 47907, USASmithsonian Astrophysical Observatory , 60 Garden Street, Cambridge, MA 02138, USAWhen the ejecta of a supernova (SN) interact with the progenitor star's circumstellar environment, a strong shock is driven back into the ejecta, causing the material to become bright optically and in X-rays. Most notably, as the shock traverses the H-rich envelope, it begins to interact with metal-rich material. Thus, continued monitoring of bright and nearby SNe provides valuable clues about both the progenitor structure and its pre-SN evolution. Here we present late-time, multiepoch optical and Chandra X-ray spectra of the core-collapse SN, SN 1996cr. Magellan IMACS optical spectra taken in 2017 July and 2021 August show a very different spectrum from that seen in 2006 with broad, double-peaked optical emission lines of oxygen, argon, and sulfur with expansion velocities of ±4500 km s ^−1 . Redshifted emission components are considerably fainter compared to the blueshifted components, presumably due to internal extinction from dust in the SN ejecta. Broad ±2400 km s ^−1 H α is also seen, which we infer is shocked progenitor pre-SN, mass-loss, H-rich material. Chandra data indicate a slow but steady decline in the overall X-ray luminosity, suggesting that the forward shock has broken through any circumstellar shell or torus, which is inferred from prior deep Chandra ACIS-S/HETG observations. The X-ray properties are consistent with what is expected from a shock breaking out into a lower-density environment. Though originally identified as a Type IIn SN, based upon late-time optical emission-line spectra, we argue that the SN 1996cr progenitor was partially or highly stripped, suggesting a Type IIb/Ib SN.https://doi.org/10.3847/1538-4357/ada15bCore-collapse supernovaeType II supernovaeType Ib supernovae |
| spellingShingle | Daniel Patnaude Kathryn E. Weil Robert A. Fesen Dan Milisavljevic Ralph P. Kraft Late-time Optical and X-Ray Emission Evolution of the Oxygen-rich SN 1996cr The Astrophysical Journal Core-collapse supernovae Type II supernovae Type Ib supernovae |
| title | Late-time Optical and X-Ray Emission Evolution of the Oxygen-rich SN 1996cr |
| title_full | Late-time Optical and X-Ray Emission Evolution of the Oxygen-rich SN 1996cr |
| title_fullStr | Late-time Optical and X-Ray Emission Evolution of the Oxygen-rich SN 1996cr |
| title_full_unstemmed | Late-time Optical and X-Ray Emission Evolution of the Oxygen-rich SN 1996cr |
| title_short | Late-time Optical and X-Ray Emission Evolution of the Oxygen-rich SN 1996cr |
| title_sort | late time optical and x ray emission evolution of the oxygen rich sn 1996cr |
| topic | Core-collapse supernovae Type II supernovae Type Ib supernovae |
| url | https://doi.org/10.3847/1538-4357/ada15b |
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