This is a composite Chandra X-ray (blue) and Palomar infrared (red and green) image that reveals a barrel-shaped supernova remnant consisting of bright infrared rings around a glowing bar of intense X-radiation. These X-rays are produced by jets of 15 million degree Celsius gas that is rich in iron and nickel. These features indicate that W49B was produced when the core of a rapidly-rotating massive star collapsed to form a black hole, triggering the ejection of high-energy jets of material. Such a sequence of events is consistent with the collapsar model for gamma-ray bursts. If confirmed, the discovery of a relatively nearby remnant of a gamma-ray burst would give scientists an excellent opportunity to study the aftermath of one of nature’s most violent explosions.