MARONGIU, MarcoMarcoMARONGIUGuidorzi, C.C.GuidorziMargutti, R.R.MarguttiCoppejans, D. L.D. L.CoppejansMartone, R.R.MartoneKamble, A.A.Kamble2025-02-042025-02-0420190004-637Xhttp://hdl.handle.net/20.500.12386/35792Broad-line type Ic Supernovae (BL-Ic SNe) are characterized by high ejecta velocity (≳10^4 km/s) and are sometimes associated with the relativistic jets typical of long duration (≳2 s) Gamma-Ray Bursts. The reason why a small fraction of BL-Ic SNe harbor relativistic jets is not known. Here we present deep X-ray and radio observations of the BL-Ic SN 2014ad extending from 13 to 930 days post explosion. SN 2014ad was not detected at either frequency and has no observational evidence of a GRB counterpart. The proximity of SN 2014ad (d ∼ 26 Mpc) enables very deep constraints on the progenitor mass-loss rate \dot{M} and on the total energy of the fast ejecta E. We consider two synchrotron emission scenarios for a wind-like circumstellar medium (CSM): (i) uncollimated nonrelativistic ejecta, and (ii) off-axis relativistic jet. Within the first scenario our observations are consistent with GRB-less BL-Ic SNe characterized by a modest energy budget of their fast ejecta (E ≲ 10^45 erg), like SNe 2002ap and 2010ay. For jetted explosions, we cannot rule out a GRB with E ≲ 10^51 erg (beam-corrected) with a narrow opening angle (θ_j ∼ 5°) observed moderately off-axis (θ_obs ≳ 30°) and expanding in a very low CSM density (\dot{M}≲ 10^-6 M⊙yr^-1). Our study shows that off-axis low-energy jets expanding in a low-density medium cannot be ruled out even in the most nearby BL-Ic SNe with extensive deep observations, and might be a common feature of BL-Ic SNe.STAMPAenArticle10.3847/1538-4357/ab25ef2-s2.0-85071950275https://iopscience.iop.org/article/10.3847/1538-4357/ab25ef2019ApJ...879...89MFIS/05 - ASTRONOMIA E ASTROFISICA