SN 2024bfu, SN 2025qe, and the early light curves of type Iax supernovae

ABSTRACT Type Iax supernovae (SNe Iax) are one of the most common subclasses of thermonuclear supernova and yet their sample size, particularly those observed shortly after explosion, remains relatively small. In this paper, we present photometric and spectroscopic observations of two SNe Iax discovered shortly after explosion, SN 2024bfu and SN 2025qe. Both SNe were observed by multiple all-sky surveys, enabling tight constraints on the moment of first light and the shape of the early light curve. Our observations of SN 2025qe begin <2 d after the estimated time of first light and represent some of the earliest observations of any SN Iax. Spectra show features consistent with carbon absorption throughout the evolution of SN 2025qe, potentially indicating the presence of unburned material throughout the ejecta. We gather a sample of SNe Iax observed by the Asteroid Terrestrial-impact Last Alert System (ATLAS), Gravitational-wave Optical Transient Observer (GOTO), and Zwicky Transient Facility (ZTF) shortly after explosion and measure their rise times and early light curve power-law rise indices. We compare our results to a sample of normal SNe Ia and find indications that SNe Iax show systematically shorter rise times, consistent with previous work. We also find some indication that SNe Iax show systematically lower rise indices than normal SNe Ia. The low rise indices observed among SNe Iax are qualitatively consistent with extended $^{56}$Ni distributions and more thoroughly-mixed ejecta compared to normal SNe Ia, similar to predictions from pure deflagration explosions.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-10-01
DOI
https://doi.org/10.1093/mnras/staf1675
Citations
5
Primary Topic
Gamma-ray bursts and supernovae
Type
article
Field-Weighted Citation Impact
5.77

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article

SN 2024bfu, SN 2025qe, and the early light curves of type Iax supernovae

E. Kankare, J. P. Anderson, J. D. Lyman, P. J. Pessi et al.
5 citations
Monthly Notices of the Royal Astronomical Society
Gamma-ray bursts and supernovae
5.77
article

SN 2024bfu, SN 2025qe, and the early light curves of type Iax supernovae

E. Kankare, J. P. Anderson, J. D. Lyman, P. J. Pessi, L. Galbany, M. Pursiainen, K. Noysena, M. Gromadzki, T. E. Müller-Bravo, D. Pollacco, S. González–Gaitán, D. R. Young, R. P. Breton, Danny T. H. Steeghs, K. Ackley, Deborah Jarvis, Richard Wilson, M. Magee, S. Mattila, Gavin Ramsay, Thomas L. Killestein, Cristina Jiménez-Palau, T. Butterley, R. Kotak, Seán Moran, Amit Kumar, O. Yaron, Desmond O’Neill, D. K. Galloway, Bob Warwick, L Kelsey, K. Ulaczyk, Jorge Casares, V. S. Dhillon, Martin J. Dyer, G. Leloudas, R. L. C. Starling, C. Inserra, Shubham Srivastav, B. Godson, T. W. Chen
article en
5 citations

Abstract

ABSTRACT Type Iax supernovae (SNe Iax) are one of the most common subclasses of thermonuclear supernova and yet their sample size, particularly those observed shortly after explosion, remains relatively small. In this paper, we present photometric and spectroscopic observations of two SNe Iax discovered shortly after explosion, SN 2024bfu and SN 2025qe. Both SNe were observed by multiple all-sky surveys, enabling tight constraints on the moment of first light and the shape of the early light curve. Our observations of SN 2025qe begin <2 d after the estimated time of first light and represent some of the earliest observations of any SN Iax. Spectra show features consistent with carbon absorption throughout the evolution of SN 2025qe, potentially indicating the presence of unburned material throughout the ejecta. We gather a sample of SNe Iax observed by the Asteroid Terrestrial-impact Last Alert System (ATLAS), Gravitational-wave Optical Transient Observer (GOTO), and Zwicky Transient Facility (ZTF) shortly after explosion and measure their rise times and early light curve power-law rise indices. We compare our results to a sample of normal SNe Ia and find indications that SNe Iax show systematically shorter rise times, consistent with previous work. We also find some indication that SNe Iax show systematically lower rise indices than normal SNe Ia. The low rise indices observed among SNe Iax are qualitatively consistent with extended $^{56}$Ni distributions and more thoroughly-mixed ejecta compared to normal SNe Ia, similar to predictions from pure deflagration explosions.

Monthly Notices of the Royal Astronomical SocietyVol. 543(4)
Queen's University Belfast (GB), University of Lisbon (PT), University of Leicester (GB), University of Turku (FI), Royal Holloway University of London (GB), Durham University (GB), European University Cyprus (CY), Trinity College Dublin (IE), National Central University (TW), University of Cambridge (GB), Armagh Observatory & Planetarium (GB), University of Manchester (GB), University of Warwick (GB), University of Oxford (GB), Institute of Astrophysics and Space Sciences (PT), Institut d'Estudis Espacials de Catalunya (ES), Millennium Institute of Astrophysics (CL), Queens University (BD), American Committee for the Weizmann Institute of Science (US), Institute of Space Sciences (ES), Physical Sciences (United States) (US), Institute of Astronomy (RU), European Southern Observatory (CL), Instituto de Astrofísica de Canarias (ES), AlbaNova (SE), Astronomical Observatory (RS), University of Warsaw (PL), Weizmann Institute of Science (IL), Monash University (AU), University of Portsmouth (GB), Cardiff University (GB), University of Birmingham (GB), National Astronomical Research Institute of Thailand (TH), University of Sheffield (GB), Arturo Prat University (CL), Technical University of Denmark (DK)
National Science Foundation, Smithsonian Institution, National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, Johns Hopkins University, Villum Fonden, University of Portsmouth, Space Telescope Science Institute, UK Research and Innovation, National Astronomical Research Institute of Thailand, European Space Agency, Leverhulme Trust, University of Leicester, University of Warwick, Queen's University Belfast, Durham University, Monash University, Queen's University, Nuclear Safety and Security Commission, Liverpool John Moores University, Isaac Newton Trust, National Central University, Turun Yliopisto, Eötvös Loránd Tudományegyetem, Agencia Nacional de Investigación y Desarrollo, Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Canarias, Smithsonian Astrophysical Observatory, Science Mission Directorate, HORIZON EUROPE Framework Programme, Science and Technology Facilities Council, Agència de Gestió d'Ajuts Universitaris i de Recerca, Agencia Estatal de Investigación, Planetary Science Division, European Social Fund, Los Alamos National Laboratory
Openalex Percentile: Top 4%
Gamma-ray bursts and supernovae
5.77
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