SN 2018gk Revisited: the Photosphere, the Central Engine, and the Putative Dust
We perform a comprehensive study of the physical properties of SN 2018gk, which is a luminous Type IIb supernova (SN). We find that the early-time photospheric velocity varies from a larger value to a smaller one before the photosphere reaches a temperature floor. We generalize the photosphere modul...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/acc24d |
| _version_ | 1827825768533590016 |
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| author | Tao Wang Shan-Qin Wang Wen-Pei Gan Long Li |
| author_facet | Tao Wang Shan-Qin Wang Wen-Pei Gan Long Li |
| author_sort | Tao Wang |
| collection | DOAJ |
| description | We perform a comprehensive study of the physical properties of SN 2018gk, which is a luminous Type IIb supernova (SN). We find that the early-time photospheric velocity varies from a larger value to a smaller one before the photosphere reaches a temperature floor. We generalize the photosphere modulus and fit the multiband light curves (LCs) of SN 2018gk. We find that the ^56 Ni mass model requires ∼0.90 M _⊙ of ^56 Ni, which is larger than the derived ejecta mass (∼0.10 M _⊙ ). Alternatively, we use the magnetar plus ^56 Ni and the fallback plus ^56 Ni models to fit the LCs of SN 2018gk, finding that the two models can fit the LCs. We favor the magnetar plus ^56 Ni model since the parameters are rather reasonable ( M _ej = 1.65 M _⊙ , M _Ni = 0.05 M _⊙ , which is smaller than the upper limit of the ^56 Ni mass that can by synthesized by neutrino-powered core-collapse SNe, B = 6.52 × 10 ^14 G, which is comparable to magnetic fields in luminous and superluminous SNe studied in the literature, and P _0 = 10.42 ms, which is comparable to initial periods for luminous SNe), while the validity of the fallback plus ^56 Ni model depends on the accretion efficiency ( η ). Therefore, we suggest that SN 2018gk might be an SN IIb powered mainly by a central engine. Finally, we confirm the near-IR excesses of the spectral energy distributions of SN 2018gk at some epochs and constrain the physical properties of the putative dust using the blackbody plus dust emission model. |
| first_indexed | 2024-03-12T02:55:10Z |
| format | Article |
| id | doaj.art-74a00217a8b24ef69d952a542748e3f6 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T02:55:10Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-74a00217a8b24ef69d952a542748e3f62023-09-03T15:18:31ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01948213810.3847/1538-4357/acc24dSN 2018gk Revisited: the Photosphere, the Central Engine, and the Putative DustTao Wang0https://orcid.org/0000-0002-4878-1227Shan-Qin Wang1https://orcid.org/0000-0001-7867-9912Wen-Pei Gan2Long Li3Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University , Nanning 530004, People's Republic of China ; shanqinwang@gxu.edu.cnGuangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University , Nanning 530004, People's Republic of China ; shanqinwang@gxu.edu.cnNanjing Institute of Astronomical Optics & Technology , Nanjing 210042, People's Republic of ChinaDepartment of Astronomy, School of Physical Sciences, University of Science and Technology of China , Hefei 230026, People's Republic of ChinaWe perform a comprehensive study of the physical properties of SN 2018gk, which is a luminous Type IIb supernova (SN). We find that the early-time photospheric velocity varies from a larger value to a smaller one before the photosphere reaches a temperature floor. We generalize the photosphere modulus and fit the multiband light curves (LCs) of SN 2018gk. We find that the ^56 Ni mass model requires ∼0.90 M _⊙ of ^56 Ni, which is larger than the derived ejecta mass (∼0.10 M _⊙ ). Alternatively, we use the magnetar plus ^56 Ni and the fallback plus ^56 Ni models to fit the LCs of SN 2018gk, finding that the two models can fit the LCs. We favor the magnetar plus ^56 Ni model since the parameters are rather reasonable ( M _ej = 1.65 M _⊙ , M _Ni = 0.05 M _⊙ , which is smaller than the upper limit of the ^56 Ni mass that can by synthesized by neutrino-powered core-collapse SNe, B = 6.52 × 10 ^14 G, which is comparable to magnetic fields in luminous and superluminous SNe studied in the literature, and P _0 = 10.42 ms, which is comparable to initial periods for luminous SNe), while the validity of the fallback plus ^56 Ni model depends on the accretion efficiency ( η ). Therefore, we suggest that SN 2018gk might be an SN IIb powered mainly by a central engine. Finally, we confirm the near-IR excesses of the spectral energy distributions of SN 2018gk at some epochs and constrain the physical properties of the putative dust using the blackbody plus dust emission model.https://doi.org/10.3847/1538-4357/acc24dSupernovaeType II supernovaeMagnetarsCircumstellar dust |
| spellingShingle | Tao Wang Shan-Qin Wang Wen-Pei Gan Long Li SN 2018gk Revisited: the Photosphere, the Central Engine, and the Putative Dust The Astrophysical Journal Supernovae Type II supernovae Magnetars Circumstellar dust |
| title | SN 2018gk Revisited: the Photosphere, the Central Engine, and the Putative Dust |
| title_full | SN 2018gk Revisited: the Photosphere, the Central Engine, and the Putative Dust |
| title_fullStr | SN 2018gk Revisited: the Photosphere, the Central Engine, and the Putative Dust |
| title_full_unstemmed | SN 2018gk Revisited: the Photosphere, the Central Engine, and the Putative Dust |
| title_short | SN 2018gk Revisited: the Photosphere, the Central Engine, and the Putative Dust |
| title_sort | sn 2018gk revisited the photosphere the central engine and the putative dust |
| topic | Supernovae Type II supernovae Magnetars Circumstellar dust |
| url | https://doi.org/10.3847/1538-4357/acc24d |
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