SN 2022joj: A Peculiar Type Ia Supernova Possibly Driven by an Asymmetric Helium-shell Double Detonation

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© 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

We thank the anonymous referee for a thoughtful report. We are grateful to Ping Chen, Avishay Gal-Yam, Anthony Piro, Anna Ho, and Jiaxuan Li for fruitful discussions, as well as to Peter Blanchard and Jillian Rastinejad for the LRIS spectra they obtained. We thank UC Berkeley undergraduate students Kate Bostow, Cooper Jacobus, Gabrielle Stewart, Edgar Vidal, Victoria Brendel, Asia deGraw, Conner Jennings, and Michael May for the Lick/Nickel photometry. K.J.S. was in part supported by NASA/ESA Hubble Space Telescope (HST) programs #15871 and #15918. S.J.B. and D.M.T. acknowledge support from NASA grant HST-AR-16156. L.H. is funded by the Irish Research Council under grant GOIPG/2020/1387. K.M. is funded by the EU H2020 European Research Council (ERC) grant 758638. S.S. acknowledges support from the G.R.E.A.T. research environment, funded by Vetenskapsr å det, the Swedish Research Council, project 2016-06012. G.D. is supported by the H2020 ERC grant 758638. C.D.K. is partly supported by a Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) postdoctoral fellowship. A.V.F.'s supernova group at UC Berkeley received generous financial assistance from the Christopher R. Redlich Fund, from Briggs and Kathleen Wood (T.G.B. is a Wood Specialist in Astronomy), from Alan Eustace (W.Z. is a Eustace Specialist in Astronomy), and from numerous other donors.

We appreciate the excellent assistance of the staff at the observatories where data were obtained. This work is based on observations obtained with the Samuel Oschin Telescope 48 inch and the 60 inch Telescope at the Palomar Observatory as part of the ZTF project. ZTF is supported by the NSF under grant AST-2034437 and a collaboration including Caltech, IPAC, the Weizmann Institute of Science, the Oskar Klein Centre at Stockholm University, the University of Maryland, Deutsches Elektronen-Synchrotron and Humboldt University, the TANGO Consortium of Taiwan, the University of Wisconsin (UW) at Milwaukee, Trinity College Dublin, Lawrence Livermore National Laboratories, IN2P3, University of Warwick, Ruhr University Bochum, and Northwestern University. Operations are conducted by Caltech Optical Observatories, IPAC, and UW. The SED Machine is based upon work supported by the NSF under grant 1106171. The ZTF forced-photometry service was funded under the Heising-Simons Foundation grant #12540303 (PI: Graham). The Gordon and Betty Moore Foundation, through both the Data-driven Investigator Program and a dedicated grant, provided critical funding for SkyPortal.

A major upgrade of the Kast spectrograph on the Shane 3 m telescope at Lick Observatory, led by Brad Holden, was made possible through generous gifts from the Heising-Simons Foundation, William and Marina Kast, and the University of California Observatories. KAIT and its ongoing operation were made possible by donations from Sun Microsystems Inc., the Hewlett-Packard Company, AutoScope Corporation, Lick Observatory, the U.S. NSF, the University of California, the Sylvia & Jim Katzman Foundation, and the TABASGO Foundation. Research at Lick Observatory is partially supported by a generous gift from Google.

This work is also based in part on observations made with the NOT, 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 (respectively 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. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA; the observatory was made possible by the generous financial support of the W. M. Keck Foundation. Observations reported here were obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona. W. M. Keck Observatory and MMT Observatory access was supported by Northwestern University and CIERA.

This work has made use of data from the ATLAS project, which is primarily funded to search for near-Earth objects (NEOs) through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen's University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and the Millennium Institute of Astrophysics (MAS), Chile.

Facilities

PO:1.2m (ZTF) - , Swift (UVOT) - , KAIT - Katzman Automatic Imaging Telescope, Nickel - Lick Observatory's 1m Nickel Telescope, Liverpool:2m (IO:O) - , PO:1.5m (SEDM) - , FTN (FLOYDS) - , FTS (FLOYDS) - , NOT (ALFOSC) - , Liverpool:2m (SPRAT) - , Keck:I (LRIS) - , MMT (Binospec) - , Hale (TSpec) - Palomar Observatory's 5.1m Hale Telescope.

Software References

astropy (Astropy Collaboration et al. 2013, 2018), dynesty (Speagle 2020), matplotlib (Hunter 2007), NumPy (Harris et al. 2020), prospector (Johnson et al. 2021), PyMC (Salvatier et al. 2016), PypeIt (Prochaska et al. 2020), pysedm (Rigault et al. 2019), sncosmo (Barbary et al. 2023), Python-FSPS (Conroy et al. 2009; Conroy & Gunn 2010; Foreman-Mackey et al. 2014), Sedona (Kasen et al. 2006), ZFPS (Masci et al. 2023).