Jets in Hydrogen-poor Super-luminous Supernovae: Constraints from a Comprehensive Analysis of Radio Observations

The energy source powering the extreme optical luminosity of hydrogen-stripped Superluminous Supernovae (SLSNe-I) is not known, but recent studies have highlighted the case for a central engine. Radio and/or X-ray observations are best placed to track the fastest ejecta and probe the presence of outflows from a central engine. We compile all the published radio observations of SLSNe-I to date and present three new observations of two new SLSNe-I. None were detected. Through modeling the radio emission, we constrain the sub-parsec environments and possible outflows in SLSNe-I. In this sample we rule out on-axis collimated relativistic jets of the kind detected in Gamma-Ray Bursts (GRBs). We constrain off-axis jets with opening angles of 5\arcdeg
(30\arcdeg) to energies of ${\mathrm{E}}_{\mathrm{k}}<4\times {10}^{50}\mathrm{e}\mathrm{r}\mathrm{g}$ (${\mathrm{E}}_{\mathrm{k}}<{10}^{50}\mathrm{e}\mathrm{r}\mathrm{g}$) in environments shaped by progenitors with mass-loss rates of $\dot{M}<{10}^{-4}{M}_{\odot }{\mathrm{y}\mathrm{r}}^{-1}$ ($\dot{M}<{10}^{-5}{M}_{\odot }{\mathrm{y}\mathrm{r}}^{-1}$) for all off-axis angles, assuming fiducial values ${ϵ}_e=0.1$ and ${ϵ}_B=0.01$. The deepest limits rule out emission of the kind seen in faint un-collimated GRBs (with the exception of GRB,060218), and from relativistic supernovae. Finally, for the closest SLSN-I SN 2017egm we constrained the energy of an uncollimated non-relativistic outflow like those observed in normal SNe to $E_{\mathrm{k}}\lesssim {10}^{48}$ erg.