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Abstract The observational link between long gamma-ray bursts (GRBs) and broad-lined stripped-envelope core-collapse supernovae (SNe Ic-BL) is well established. Significant progress has been made in constraining what fraction of SNe Ic-BL may power high- or low-luminosity GRBs when viewed at small off-axis angles. However, the GRB–SN connection still lacks a complete understanding in the broader context of massive-star evolution and explosion physics. Models predict a continuum of outcomes for the fastest ejecta, from choked to ultrarelativistic jets, and observations from radio to X-rays are key to probing these scenarios across a range of viewing angles and velocities. Here, we present results from a coordinated radio-to-X-ray campaign targeting nearby (z ≲ 0.1) SNe Ic-BL designed to explore this diversity. With eight new radio-monitored events and updated data for one previously observed SN, we further tighten constraints on the fraction of SNe Ic-BL as relativistic as SN 1998bw (GRB 980425). We identify SN 2024rjw as a new radio-loud event likely powered by strong interaction with circumstellar material, and add evidence supporting a similar interpretation for SN 2020jqm. We also establish new limits on the properties of radio-emitting ejecta with velocities consistent with cocoons from choked jets, highlighting SN 2022xxf as a promising cocoon-dominated candidate. These results refine our understanding of the continuum linking ordinary SNe Ic-BL, engine-driven explosions, and GRBs, and contribute to building a sample that will inform future multimessenger searches for electromagnetic counterparts to high-energy neutrinos.
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This content will become publicly available on December 4, 2026
A Late-time Radio Search for Highly Off-axis Jets from PTF Broad-lined Ic Supernovae in GRB-like Host Galaxy Environments
Abstract Hydrogen/helium-poor stripped-envelope core-collapse supernovae with broad lines (SNe Ic-bl) almost always accompany the nearby (z < 0.3) jetted relativistic explosions known as long duration gamma-ray bursts (GRBs). However, the majority of SNe Ic-bl have no detected GRB counterpart. At least some of these SNe should harbor off-axis jets, whose afterglow may become detectable at late times, particularly at radio wavelengths. Here, we present Karl G. Jansky Very Large Array (VLA) radio observations (rest-frame times of ∼3–4 × 103days post SN discovery) of a sample of 14 SNe Ic-bl discovered by the Palomar Transient Factory (PTF) that have been demonstrated to originate from the same host environments as the SNe Ic-bl associated with nearby GRBs. Of the 14 SNe, we identify three that are radio detected, one of which (PTF10tqv,z= 0.0795) is consistent with an off-axis jet with energy similar to classical GRBs (∼1051–1051.7erg). Using recently developed synchrotron radiation code, we find that for our 11 nondetections, which are among the deepest limits obtained for Ic-bl, we rule out an off-axis jet with an energy of ≳1051erg in circumburst densities of ≳10−1cm−3. We predict that well-spaced monitoring of newly discovered SNe Ic-bl from ∼10 days to ∼10 yr (rest frame) to luminosities of ∼1027erg s−1Hz−1will constrain the existence of highly off-axis jets (≳60°) with classical GRB energies. The VLA Sky Survey will probe jets that are ≲60° off-axis, whereas the Deep Synpotic Array 2000 will probe jets out to ∼90° off-axis, demonstrating the importance of utilizing radio surveys to supplement targeted observations.
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- PAR ID:
- 10705081
- Publisher / Repository:
- The Astrophysical Journal
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 995
- Issue:
- 1
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- 61
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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