Published February 2025 | Published
Journal Article Open

ZTF SN Ia DR2: The diversity and relative rates of the thermonuclear supernova population

  • 1. ROR icon Trinity College Dublin
  • 2. ROR icon Lancaster University
  • 3. ROR icon Stockholm University
  • 4. ROR icon Claude Bernard University Lyon 1
  • 5. ROR icon University of Southampton
  • 6. ROR icon Institute of Space Sciences
  • 7. ROR icon Institut d'Estudis Espacials de Catalunya
  • 8. ROR icon Northwestern University
  • 9. ROR icon Lawrence Berkeley National Laboratory
  • 10. ROR icon University of California, Berkeley
  • 11. ROR icon Weizmann Institute of Science
  • 12. ROR icon University of Cambridge
  • 13. ROR icon California Institute of Technology
  • 14. ROR icon Infrared Processing and Analysis Center
  • 15. ROR icon Humboldt-Universität zu Berlin

Abstract

The Zwicky Transient Facility SN Ia Data Release 2 (ZTF SN Ia DR2) contains more than 3000 Type Ia supernovae (SNe Ia), providing the largest homogeneous low-redshift sample of SNe Ia. Having at least one spectrum per event, this data collection is ideal for large-scale statistical studies of the photometric, spectroscopic and host-galaxy properties of SNe Ia, particularly of the rarer 'peculiar' sub-classes. In this paper we first present the method we developed to spectroscopically classify the SNe in the sample, and the techniques we used to model their multi-band light curves and explore their photometric properties. We then show a method to distinguish between the peculiar sub-types and the normal SNe Ia. We also explore the properties of their host galaxies and estimate their relative rates, focusing on the peculiar sub-types and their connection to the cosmologically useful SNe Ia. Finally, we discuss the implications of our study with respect to the progenitor systems of the peculiar SN Ia events.

Copyright and License

© The Authors 2025.

Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Acknowledgement

We thank the anonymous referee for helpful comments that improved the clarity and presentation of this paper. Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grants No. AST-1440341 and AST-2034437 and a collaboration including current partners Caltech, IPAC, the Weizmann Institute of Science, the Oskar Klein Center at Stockholm University, the University of Maryland, Deutsches Elektronen-Synchrotron and Humboldt University, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, Trinity College Dublin, Lawrence Livermore National Laboratories, IN2P3, University of Warwick, Ruhr University Bochum, Northwestern University and former partners the University of Washington, Los Alamos National Laboratories, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW. SED Machine is based upon work supported by the National Science Foundation under Grant No. 1106171. The ZTF forced-photometry service was funded under the Heising-Simons Foundation grant #12540303 (PI: Graham). This work was supported by the GROWTH project funded by the National Science Foundation under Grant No 1545949 (Kasliwal et al. 2019). Fritz (van der Walt et al. 2019Coughlin et al. 2023) is used in this work. The Gordon and Betty Moore Foundation, through both the Data-Driven Investigator Program and a dedicated grant, provided critical funding for SkyPortal. GD, UB, MD, KM, and JHT are supported by the H2020 European Research Council grant no. 758638. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement n 759194 – USNAC). LG, AA and TEMB acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación (MCIN) and the Agencia Estatal de Investigación (AEI) 10.13039/501100011033 under the PID2020-115253GA-I00 HOSTFLOWS project, and from Centro Superior de Investigaciones Científicas (CSIC) under the PIE project 20215AT016 and the program Unidad de Excelencia María de Maeztu CEX2020-001058-M. LG acknowledges financial support from the Departament de Recerca i Universitats de la Generalitat de Catalunya through the 2021-SGR-01270 grant. KP acknowledges financial support from AGAUR, CSIC, MCIN and AEI 10.13039/501100011033 under projects PID2023-151307NB-I00, PIE 20215AT016, CEX2020-001058-M, and 2021-SGR-01270. TEMB acknowledges financial support from the European Union Next Generation EU/PRTR funds under the 2021 Juan de la Cierva program FJC2021-047124-I. Y-LK has received funding from the Science and Technology Facilities Council [grant number ST/V000713/1]. AAM is partially supported by LBNL Subcontract NO. 7707915. SD acknowledges support from a Kavli Fellowship and a Junior Research Fellowship at Lucy Cavendish College. This work has been supported by the research project grant “Understanding the Dynamic Universe” funded by the Knut and Alice Wallenberg Foundation under Dnr KAW 2018.0067 and the Vetenskapsrådet, the Swedish Research Council, project 2020-03444. LH is funded by the Irish Research Council under grant number GOIPG/2020/1387.

Data Availability

The full version of Table A.2 is available at the CDS via anonyous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/694/A10

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Additional details

Created:
February 20, 2025
Modified:
February 20, 2025