iPTF17cw: An engine-driven supernova candidate discovered independent of a gamma-ray trigger

Understand

We present the discovery, classification, and radio-to-X-ray follow-up observations of iPTF17cw, a broad-lined (BL) type Ic supernova (SN) discovered by the intermediate Palomar Transient Factory (iPTF).

• Although unrelated to the gravitational wave trigger, this SN was discovered as a happy by-product of the extensive observational campaign dedicated to the follow-up of Advanced LIGO event GW170104.
• The spectroscopic properties and inferred peak bolometric luminosity of iPTF17cw are most similar to the gamma-ray burst (GRB) associated SN 1998bw, while the shape of the r-band light curve is most similar to that of the relativistic SN 2009bb.
• Karl G.