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Long-duration gamma-ray bursts (GRBs) are almost unequivocally associatedwith very energetic, broad-lined supernovae (SNe) of Type Ic-BL. While thegamma-ray emission is emitted in narrow jets, the SN emits radiationisotropically. Therefore, some SN Ic-BL not associated with GRBs have beenhypothesized to arise from events with inner engines such as off-axis GRBs orchoked jets. Here we present observations of the nearby ($d = 120$ Mpc) SN2020bvc (ASAS-SN 20bs) which support this scenario. \textit{Swift} UVOTobservations reveal an early decline (up to two days after explosion) whileoptical spectra classify it as a SN Ic-BL with very high expansion velocities($\approx$ 70,000 km/s), similar to that found for the jet-cocoon emission inSN 2017iuk associated with GRB 171205A. Moreover, \textit{Swift} X-RayTelescope and \textit{CXO} X-ray Observatory detected X-ray emission only threedays after the SN and decaying onwards, which can be ascribed to an afterglowcomponent. Cocoon and X-ray emission are both signatures of jet-powered GRBs.In the case of SN 2020bvc, we find that the jet is off axis (by $\approx$ 23degrees), as also indicated by the lack of early ($\approx 1$ day) X-rayemission which explains why no coincident GRB was detected promptly or inarchival data. These observations suggest that SN 2020bvc is the first orphanGRB detected through its associated SN emission.

The broad-line type Ic SN 2020bvc: signatures of an off-axis gamma-ray burst afterglow