| Title: |
SN 2019tsf: Evidence for Extended Hydrogen-poor CSM in the Three-peaked Light Curve of Stripped Envelope of a Type Ib Supernova |
| Authors: |
Zenati, Y; Wang, Q; Bobrick, A; DeMarchi, L; Glanz, H; Rozner, M; Jencson, JE; Rest, A; Metzger, BD; Margutti, R; Gomez, S; Smith, N; Toonen, S; Bright, JS; Norman, C; Foley, RJ; Gagliano, A; Krolik, JH; Smartt, SJ; Villar, AV; Narayan, G; Fox, O; Auchettl, K; Brethauer, D |
| Publisher Information: |
American Astronomical Society |
| Publication Year: |
2025 |
| Collection: |
Oxford University Research Archive (ORA) |
| Description: |
We present multiband ATLAS and ZTF photometry for SN 2019tsf, a Type Ib stripped-envelope supernova (SESN). The slow spectral evolution could be associated with an uncommon explosion mechanism specific to this SN. Possible explanations include fallback accretion onto a compact remnant or a long-lived central engine, both of which could provide extended energy injection responsible for the late-time rebrightening and unusual spectral features. The rebrightening observations represent the latest photometric measurements of a multipeaked Type Ib SN. As late-time photometry and spectroscopy suggest no hydrogen, the potential circumstellar material (CSM) must be H-poor. The absence of a nebular phase and the lack of narrow emission lines in the late-time spectra (>142 days) of the SNe suggest that any CSM interaction is likely asymmetric and enveloped by the SN ejecta. However, an extended CSM structure is evident through a follow-up radio campaign with the Karl G. Jansky Very Large Array (VLA), indicating a source of bright optically thick radio emission at late times, which is highly unusual among H-poor SESNe. We attribute this phenomenology to an interaction of the supernova ejecta with asymmetric CSM, potentially disk-like, and we present several models that may explain the origin of this rare Type Ib supernova. We propose a warped disk model in which a tertiary companion—commonly present around massive stars—perturbs the progenitor’s CSM, producing density enhancements that may explain the observed multipeaked SN 2019tsf light curve. This SN 2019tsf is a unique SN Type Ib among the recently discovered class of SNe that undergo mass transfer at the moment of explosion. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.3847/1538-4357/adf6b1 |
| Availability: |
https://doi.org/10.3847/1538-4357/adf6b1; https://ora.ox.ac.uk/objects/uuid:0b819412-219b-4eb5-b533-80e2b77ccdb6 |
| Rights: |
info:eu-repo/semantics/openAccess ; CC Attribution (CC BY) |
| Accession Number: |
edsbas.14242FD9 |
| Database: |
BASE |