SN 2023tsz: a helium-interaction-driven supernova in a very low-mass galaxy
SN 2023tsz is a Type Ibn supernova (SN Ibn), an uncommon subtype of stripped-envelope core-collapse supernovae (SNe), discovered in an extremely low-mass host. SNe Ibn are characterized by narrow helium emission lines in their spectra and are believed to originate from the collapse of massive Wolf–Rayet (WR) stars, though their progenitor systems still remain poorly understood. In terms of energetics and spectrophotometric evolution, SN 2023tsz is largely a typical example of the class, although line profile asymmetries in the nebular phase are seen, which may indicate the presence of dust formation or unshocked circumstellar material. Intriguingly, SN 2023tsz is located in an extraordinarily low-mass host galaxy that is in the second percentile for stripped-envelope SN host masses and star formation rates (SFRs). The host has a radius of 1.0 kpc, a g-band absolute magnitude of $-12.72 \pm 0.05$, and an estimated metallicity of $\log (Z_{*}/{\rm Z}_{\odot }) \approx -1.6$. The SFR and metallicity of the host galaxy raise questions about the progenitor of SN 2023tsz. The low SFR suggests that a star with sufficient mass to evolve into a WR would be uncommon in this galaxy. Further, the very low metallicity is a challenge for single stellar evolution to enable H and He stripping of the progenitor and produce an SN Ibn explosion. The host galaxy of SN 2023tsz adds another piece to the ongoing puzzle of SNe Ibn progenitors, and demonstrates that they can occur in hosts too faint to be observed in contemporary sky surveys at a more typical SN Ibn redshift.
Funding
New frontiers in transient astrophysics: gravitational-wave multi-messenger events and exotic stellar explosions
UK Research and Innovation
Find out more...Warwick Astronomy & Astrophysics Consolidated Grant 2023-2026
Science and Technology Facilities Council
Find out more...TLK acknowledges support via a Research Council of Finland grant (340613; PI: R. Kotak), and from the STFC, grant number ST/T506503/1).
SM was funded by the Research Council of Finland project 350458.
Multi-band, Multi-messenger Astrophysics with LIGO, LISA and GOTO
UK Research and Innovation
Find out more...The Gravitational wave Optical Transient Observer
Science and Technology Facilities Council
Find out more...The Gravitational wave Optical Transient Observer - facility operations 2024-2027
Science and Technology Facilities Council
Find out more...JPA’s work was funded by the National Agency for Research and Development (ANID), Millennium Science Initiative, ICN12_009. TP acknowledges the financial support from the Slovenian Research Agency (grants I0-0033, P1-0031, J1-8136, J1-2460, and Z1-1853). PC was supported by the STFC (grants ST/S000550/1 and ST/W001225/1). RS was funded by a Leverhulme Research Project Grant. MJD was funded by the STFC as part of the GOTO project (grant number ST/V000853/1). MRM acknowledges a Warwick Astrophysics prize post-doctoral fellowship made possible thanks to a generous philanthropic donation AS acknowledges the Warwick Astrophysics PhD prize scholarship made possible thanks to a generous philanthropic donation. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, as part of ePESSTO+ (the advanced Public ESO Spectroscopic Survey for Transient Objects Survey). ePESSTO+ observations were obtained under ESO program ID 112.25JQ. AA acknowledges the Yushan Fellow Program by the Ministry of Education, Taiwan for the financial support (MOE-111-YSFMS-0008-001-P1). This research has made use of data obtained from the High Energy Astrophysics Science Archive Research Center (HEASARC) and the Leicester Database and Archive Service (LEDAS), provided by NASA’s Goddard Space Flight Center and the School of Physics and Astronomy, University of Leicester, UK, respectively. LG, TEM-B, and CPG acknowledge financial support from AGAUR, CSIC, MCIN, and AEI10.13039/501100011033 under projects PID2023-151307NB-I00, PIE 20215AT016, CEX2020-001058-M, FJC2021-047124-I, 2021-BP-00168, and 2021-SGR-01270. MN was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 Framework Programme (grant agreement no. 948381) and by UK Space Agency grant no. ST/Y000692/1. TWC acknowledges the Yushan Fellow Program by the Ministry of Education, Taiwan for the financial support (MOE-111-YSFMS-000
History
Author affiliation
College of Science & Engineering Physics & AstronomyVersion
- VoR (Version of Record)
