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Title: Radio Observations of a Sample of Broad-Line Type IC Supernovae Discovered by PTF/IPTF: A Search for Relativistic Explosions

Long duration γ-ray bursts are a rare subclass of stripped-envelope core-collapse supernovae (SNe) that launch collimated relativistic outflows (jets). All γ-ray-burst-associated SNe are spectroscopically Type Ic, with broad-lines, but the fraction of broad-lined SNe Ic harboring low-luminosity γ-ray bursts remains largely unconstrained. Some SNe should be accompanied by off-axis γ-ray burst jets that initially remain invisible, but then emerge as strong radio sources (as the jets decelerate). However, this critical prediction of the jet model for γ-ray bursts has yet to be verified observationally. Here, we present K. G. Jansky Very Large Array observations of 15 broad-lined SNe of Type Ic discovered by the Palomar Transient Factory in an untargeted manner. Most of the SNe in our sample exclude radio emission observationally similar to that of the radio-loud, relativistic SN 1998bw. We constrain the fraction of 1998bw-like broad-lined SNe Ic to be $$\lesssim 41 \% $$ (99.865% confidence). Most of the events in our sample also exclude off-axis jets similar to GRB 031203 and GRB 030329, but we cannot rule out off-axis γ-ray bursts expanding in a low-density wind environment. Three SNe in our sample are detected in the radio. PTF11qcj and PTF14dby show late-time radio emission with average ejecta speeds of ≈0.3–0.4 c, on the dividing line between relativistic and "ordinary" SNe. The speed of PTF11cmh radio ejecta is poorly constrained. We estimate that $$\lesssim 85 \% $$ (99.865% confidence) of the broad-lined SNe Ic in our sample may harbor off-axis γ-ray bursts expanding in media with densities in the range probed by this study.
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [3] ;  [4] ; ORCiD logo [5] ; ORCiD logo [6] ; ORCiD logo [3] ; ORCiD logo [3] ;  [2] ; ORCiD logo [1] ; ORCiD logo [7] ;  [3] ;  [8] ; ORCiD logo [9] ; ORCiD logo [10] ; ORCiD logo [11] ;  [3] ; ORCiD logo [12]
  1. Texas Tech Univ., Lubbock, TX (United States)
  2. Weizmann Institute of Science, Rehovot (Israel)
  3. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  4. National Radio Astronomy Observatory, Socorro, NM (United States)
  5. Liverpool John Moores Univ., Liverpool (United Kingdom); Max-Planck Institut fur Astrophysik, Garching (Germany)
  6. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Univ. of Maryland, College Park, MD (United States)
  7. Univ. of Copenhagen, Copenhagen (Denmark)
  8. Stockholm Univ., Stockholm (Sweden)
  9. Weizmann Institute of Science, Rehovot (Israel); Univ. of Copenhagen, Copenhagen (Denmark)
  10. Queen's Univ. Belfast, Belfast (United Kingdom)
  11. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  12. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 830; Journal Issue: 1; Journal ID: ISSN 1538-4357
Institute of Physics (IOP)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; gamma-ray burst: general; radiation mechanisms: non-thermal; supernovae: general
OSTI Identifier: