Radio view of a broad-line Type Ic supernova ASASSN-16fp. Issue 1 (13th March 2020)

• Record Type: Journal Article
• Authors: A. J., Nayana; Chandra, Poonam
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 494:Issue 1(2020)
• Page Start: 84
• Page End: 96
• Publication Date: 2020-03-13
• Subjects: radiation mechanisms: non-thermal -- circumstellar matter -- supernovae: general -- radio continuum: general; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa700
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present extensive radio observations of a Type Ic supernova, ASASSN-16fp. Our data represent the lowest frequency observations of the supernova beyond 1000 d with a frequency range of 0.33–25 GHz and a temporal range of ∼8–1136 d post-explosion. The observations are best represented by a model of synchrotron emission from a shocked circumstellar shell initially suppressed by synchrotron self-absorption. Assuming equipartition of energy between relativistic particles and magnetic fields, we estimate the velocity and radius of the blast wave to be $v$ ∼ 0.15 c and r ∼ 3.4 × 10 15 cm, respectively, at t 0 ∼ 8 d post-explosion. We infer the total internal energy of the radio-emitting material evolves as E ∼ 0.37 × 10 47 ( t / t 0 ) 0.65 erg. We determine the mass-loss rate of the progenitor star to be $\dot{M} \sim (0.4\!-\!3.2) \times 10^{-5}\, \mathrm{M}_{\odot }\, \rm yr^{-1}$ at various epochs post-explosion, consistent with the mass-loss rate of Galactic Wolf–Rayet stars. The radio light curves and spectra show a signature of density enhancement in the circumstellar medium at a radius of ∼1.10 × 10 16 cm from the explosion centre.