SN 2023gpw: Exploring the diversity and power sources of hydrogen-rich superluminous supernovae

We present our observations and analysis of SN 2023gpw, a hydrogen-rich superluminous supernova (SLSN II) with broad emission lines in its post-peak spectra. Unlike previously observed SLSNe II, its light curve suggests an abrupt drop during a solar conjunction between ∼80 and ∼180 d after the light curve peak, which is possibly analogous to a normal hydrogen-rich supernova (SN). Spectra taken at and before the peak show hydrogen and helium “flash” emission lines attributed to early interaction with a dense confined circumstellar medium (CSM). A well-observed ultraviolet excess appears as these lines disappear, also as a result of CSM interaction. The blackbody photosphere expands roughly at the same velocity throughout the observations, indicating little or no bulk deceleration. This velocity is much higher than what is seen in spectral lines, suggesting asymmetry in the ejecta. The high total radiated energy (≳9 × 10 50 erg) and aforementioned lack of bulk deceleration in SN 2023gpw are difficult to reconcile with a neutrino-driven SN simply combined with efficient conversion from kinetic energy to emission through interaction. This suggests an additional energy source, such as a central engine. While magnetar-powered models qualitatively similar to SN 2023gpw exist, more modeling work is required to determine if they can reproduce the observed properties in combination with early interaction. The required energy might alternatively be provided by accretion onto a black hole created in the collapse of a massive progenitor star.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-10-03
DOI
https://doi.org/10.1051/0004-6361/202555588
Citations
1
Primary Topic
Gamma-ray bursts and supernovae
Type
article
Field-Weighted Citation Impact
1.15

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article

SN 2023gpw: Exploring the diversity and power sources of hydrogen-rich superluminous supernovae

T.E Müller-Bravo, T. Nagao, R. Smith, Kaustav K. Das et al.
1 citations
Astronomy and Astrophysics
Gamma-ray bursts and supernovae
1.15
article

SN 2023gpw: Exploring the diversity and power sources of hydrogen-rich superluminous supernovae

T.E Müller-Bravo, T. Nagao, R. Smith, Kaustav K. Das, C. Fremling, P. Charalampopoulos, S. Mattila, L. Yan, M. Stritzinger, Russ R. Laher, R. Kotak, T. Kangas, D. A. Perley, S.L. Groom, C. P. Gutiérrez, S. Schulze, J. Sollerman, P. Lundqvist, N. Elias–Rosa, L. Galbany, M. M. Kasliwal
article en
1 citations

Abstract

We present our observations and analysis of SN 2023gpw, a hydrogen-rich superluminous supernova (SLSN II) with broad emission lines in its post-peak spectra. Unlike previously observed SLSNe II, its light curve suggests an abrupt drop during a solar conjunction between ∼80 and ∼180 d after the light curve peak, which is possibly analogous to a normal hydrogen-rich supernova (SN). Spectra taken at and before the peak show hydrogen and helium “flash” emission lines attributed to early interaction with a dense confined circumstellar medium (CSM). A well-observed ultraviolet excess appears as these lines disappear, also as a result of CSM interaction. The blackbody photosphere expands roughly at the same velocity throughout the observations, indicating little or no bulk deceleration. This velocity is much higher than what is seen in spectral lines, suggesting asymmetry in the ejecta. The high total radiated energy (≳9 × 10 50 erg) and aforementioned lack of bulk deceleration in SN 2023gpw are difficult to reconcile with a neutrino-driven SN simply combined with efficient conversion from kinetic energy to emission through interaction. This suggests an additional energy source, such as a central engine. While magnetar-powered models qualitatively similar to SN 2023gpw exist, more modeling work is required to determine if they can reproduce the observed properties in combination with early interaction. The required energy might alternatively be provided by accretion onto a black hole created in the collapse of a massive progenitor star.

Astronomy and AstrophysicsVol. 705
California Institute of Technology (US), Institute of Space Sciences (ES), Stockholm University (SE), Turku Centre for Computer Science (FI), Aarhus University (DK), Trinity College Dublin (IE), Northwest University (CN), Institut d'Estudis Espacials de Catalunya (ES), Osservatorio Astronomico di Padova (IT), Infrared Processing and Analysis Center (US), Liverpool John Moores University (GB), Arturo Prat University (CL), Aalto University (FI)
National Science Foundation, California Institute of Technology, Northwestern University, Aarhus Universitet, University of Warwick, European Commission, Trinity College Dublin, Weizmann Institute of Science, Generalitat de Catalunya, Ministerio de Ciencia e Innovación, Stockholms Universitet, Instituto de Astrofísica de Canarias, HORIZON EUROPE Framework Programme, Deutsches Elektronen-Synchrotron, Agencia Estatal de Investigación, Institut National de Physique Nucléaire et de Physique des Particules
Openalex Percentile: Top 16%
Gamma-ray bursts and supernovae
1.15
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