Abstract
Narrow transient emission lines (flash-ionization features) in early supernova (SN) spectra trace the presence of circumstellar material (CSM) around the massive progenitor stars of core-collapse SNe. The lines disappear within days after the SN explosion, suggesting that this material is spatially confined, and originates from enhanced mass loss shortly (months to a few years) prior to the explosion. We performed a systematic survey of H-rich (Type II) SNe discovered within less than 2 days from the explosion during the first phase of the Zwicky Transient Facility survey (2018-2020), finding 30 events for which a first spectrum was obtained within <2 days from the explosion. The measured fraction of events showing flash-ionization features (>36% at the 95% confidence level) confirms that elevated mass loss in massive stars prior to SN explosion is common. We find that SNe II showing flash-ionization features are not significantly brighter, nor bluer, nor more slowly rising than those without. This implies that CSM interaction does not contribute significantly to their early continuum emission, and that the CSM is likely optically thin. We measured the persistence duration of flash-ionization emission and find that most SNe show flash features for ≈5 days. Rarer events, with persistence timescales >10 days, are brighter and rise longer, suggesting these may be intermediate between regular SNe II and strongly interacting SNe IIn.
| Original language | English |
|---|---|
| Article number | 119 |
| Number of pages | 23 |
| Journal | Astrophysical Journal |
| Volume | 952 |
| Issue number | 2 |
| DOIs | |
| State | Published - 21 Jul 2023 |
Bibliographical note
Publisher Copyright:© 2023. The Author(s). Published by the American Astronomical Society.
Funding
We thank the anonymous referee for the constructive and helpful review of our work. A.G.Y.’s research is supported by the EU via ERC grant No. 725161, the ISF GW excellence center, an IMOS space infrastructure grant, and BSF/Transformative and GIF grants, as well as The Benoziyo Endowment Fund for the Advancement of Science, the Deloro Institute for Advanced Research in Space and Optics, The Veronika A. Rabl Physics Discretionary Fund, Paul and Tina Gardner, Yeda-Sela, and the WIS-CIT joint research grant; A.G.Y. is a recipient of the Helen and Martin Kimmel Award for Innovative Investigation. N.L.S. is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) via the Walter Benjamin program—461903330. SEDm is based upon work supported by the National Science Foundation under grant No. 1106171. The ztfquery code was funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 759194—USNAC, PI: Rigault). The ZTF forced-photometry service was funded under the Heising-Simons Foundation grant No. 12540303 (PI: Graham). Based on observations obtained with the Samuel Oschin 48-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under grant No. AST-1440341 and a collaboration, including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW. Based on observations made with the Nordic Optical Telescope, owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku, and the University of Oslo, representing Denmark, Finland, and Norway, the University of Iceland and Stockholm University at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias.Based on observations obtained at the international Gemini Observatory, a program of NSF’s NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. on behalf of the Gemini Observatory partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This research has made use of the NASA/IPAC Extragalactic Database (NED), which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology.
| Funders | Funder number |
|---|---|
| Deloro Institute for Advanced Research in Space and Optics | |
| Deutsches Elektronen-Synchrotron and Humboldt University | |
| IPAC | |
| WIS-CIT | |
| Weizmann Institute for Science | |
| National Science Foundation | 1106171 |
| National Aeronautics and Space Administration | |
| Lawrence Berkeley National Laboratory | |
| University of Wisconsin-Milwaukee | |
| California Institute of Technology | |
| Aarhus Universitet | |
| University of Washington | |
| University of Maryland | |
| Los Alamos National Laboratory | |
| Horizon 2020 Framework Programme | 759194 |
| Heising-Simons Foundation | 12540303, AST-1440341 |
| National Research Council Canada | |
| European Commission | 725161 |
| European Commission | |
| Deutsche Forschungsgemeinschaft | 461903330 |
| German-Israeli Foundation for Scientific Research and Development | |
| Ministerio de Ciencia, Tecnología e Innovación | |
| Korea Astronomy and Space Science Institute | |
| Israel Science Foundation | |
| Universitetet i Oslo | |
| Háskóli Íslands | |
| Turun Yliopisto | |
| Stockholms Universitet | |
| Ministério da Ciência, Tecnologia, Inovações e Comunicações | |
| Benoziyo Endowment Fund for the Advancement of Science | |
| Agencia Nacional de Investigación y Desarrollo | |
| Instituto de Astrofísica de Canarias |