The Double-peaked Radio Light Curve of Supernova PTF11qcj

• Published in: The Astrophysical journal Vol. 872; no. 2; pp. 201 - 209
• Main Authors: Palliyaguru, Nipuni T., Corsi, Alessandra, Frail, Dale A., Vinkó, Jozsef, Wheeler, J. Craig, Gal-Yam, Avishay, Cenko, S. Bradley, Kulkarni, Shrinivas R., Kasliwal, Mansi M.
• Format: Journal Article
• Language: English
• Published: Goddard Space Flight Center The American Astronomical Society 20.02.2019; AAS; IOP Publishing
• Subjects: Astronomy; Astrophysics; Density; Ejecta; Gamma ray bursts; Gamma rays; Light curve; Luminosity; Radio; Radio observation; Supernova; supernovae: general; supernovae: individual (PTF11qcj)
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/aaf64d

We present continued radio and X-ray follow-up observations of PTF11qcj, a highly energetic broad-lined Type Ic supernova (SN), with a radio peak luminosity comparable to that of the γ-ray burst (GRB) associated SN 1998bw. The latest radio observations, carried out with the Karl G. Jansky Very Large Array, extend up to ∼5 yr after the PTF11qcj optical discovery. The radio light curve shows a double-peak profile, possibly associated with density variations in the circumstellar medium (CSM), or with the presence of an off-axis GRB jet. Optical spectra of PTF11qcj taken during both peaks of the radio light curve do not show the broad H features typically expected from H-rich circumstellar interaction. Modeling of the second radio peak within the CSM-interaction scenario requires a flatter density profile and an enhanced progenitor mass-loss rate compared to those required to model the first peak. Our radio data alone cannot rule out the alternative scenario of an off-axis GRB powering the second radio peak, but the derived GRB parameters are somewhat unusual compared to typical values found for cosmological long GRBs. On the other hand, Chandra X-ray observations carried out during the second radio peak are compatible with the off-axis GRB hypothesis, within the large measurement errors. We conclude that VLBI measurements of the PTF11qcj radio ejecta are needed to unambiguously confirm or rule out the off-axis GRB jet scenario.